diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/ComplianceClient.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/ComplianceClient.java
index 7f1d2095d6ef..7dfdbc833e6f 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/ComplianceClient.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/ComplianceClient.java
@@ -41,6 +41,7 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -355,6 +356,7 @@
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class ComplianceClient implements BackgroundResource {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/ComplianceSettings.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/ComplianceSettings.java
index 27c7f1a83381..67b1e8395ec5 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/ComplianceSettings.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/ComplianceSettings.java
@@ -43,6 +43,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -93,6 +94,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class ComplianceSettings extends ClientSettings<ComplianceSettings> {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/EchoClient.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/EchoClient.java
index 94d3fef234b5..951b15c1a69c 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/EchoClient.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/EchoClient.java
@@ -49,6 +49,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -364,6 +365,7 @@
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class EchoClient implements BackgroundResource {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/EchoSettings.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/EchoSettings.java
index e070b3fe7f45..55ce20f85076 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/EchoSettings.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/EchoSettings.java
@@ -49,6 +49,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -124,6 +125,7 @@
  *     .build();
  * }</pre>
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class EchoSettings extends ClientSettings<EchoSettings> {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/IdentityClient.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/IdentityClient.java
index dfa80e1a7fc8..2a08bf0f7598 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/IdentityClient.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/IdentityClient.java
@@ -42,6 +42,7 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -286,6 +287,7 @@
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class IdentityClient implements BackgroundResource {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/IdentitySettings.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/IdentitySettings.java
index f998c45023f9..2e530db81883 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/IdentitySettings.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/IdentitySettings.java
@@ -45,6 +45,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -95,6 +96,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class IdentitySettings extends ClientSettings<IdentitySettings> {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/MessagingClient.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/MessagingClient.java
index 673923e8e85f..4f2f1f868ca1 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/MessagingClient.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/MessagingClient.java
@@ -50,6 +50,7 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -449,6 +450,7 @@
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class MessagingClient implements BackgroundResource {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/MessagingSettings.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/MessagingSettings.java
index 5a7a29216fda..302303c985ea 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/MessagingSettings.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/MessagingSettings.java
@@ -50,6 +50,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -125,6 +126,7 @@
  *     .build();
  * }</pre>
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class MessagingSettings extends ClientSettings<MessagingSettings> {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/SequenceServiceClient.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/SequenceServiceClient.java
index bc5d66536374..f3e48827b712 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/SequenceServiceClient.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/SequenceServiceClient.java
@@ -43,6 +43,7 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -309,6 +310,7 @@
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class SequenceServiceClient implements BackgroundResource {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/SequenceServiceSettings.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/SequenceServiceSettings.java
index ef27a713df99..37903aadff11 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/SequenceServiceSettings.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/SequenceServiceSettings.java
@@ -45,6 +45,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -96,6 +97,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class SequenceServiceSettings extends ClientSettings<SequenceServiceSettings> {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/TestingClient.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/TestingClient.java
index c941dc9676fe..aea75b7a86e3 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/TestingClient.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/TestingClient.java
@@ -42,6 +42,7 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -318,6 +319,7 @@
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class TestingClient implements BackgroundResource {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/TestingSettings.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/TestingSettings.java
index 7bd64be2153a..016da734f965 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/TestingSettings.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/TestingSettings.java
@@ -46,6 +46,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -96,6 +97,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class TestingSettings extends ClientSettings<TestingSettings> {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/ComplianceStub.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/ComplianceStub.java
index 022d3dee15f1..35789202d361 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/ComplianceStub.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/ComplianceStub.java
@@ -35,6 +35,7 @@
 import com.google.showcase.v1beta1.RepeatRequest;
 import com.google.showcase.v1beta1.RepeatResponse;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -42,6 +43,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public abstract class ComplianceStub implements BackgroundResource {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/ComplianceStubSettings.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/ComplianceStubSettings.java
index 43de8c07b6ea..a82d26feb9b8 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/ComplianceStubSettings.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/ComplianceStubSettings.java
@@ -65,6 +65,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -115,6 +116,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/EchoStub.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/EchoStub.java
index 6eeddc421c3d..cd41c825e38a 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/EchoStub.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/EchoStub.java
@@ -55,6 +55,7 @@
 import com.google.showcase.v1beta1.WaitRequest;
 import com.google.showcase.v1beta1.WaitResponse;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -62,6 +63,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public abstract class EchoStub implements BackgroundResource {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/EchoStubSettings.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/EchoStubSettings.java
index 757b99eb640f..c62be894bd9b 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/EchoStubSettings.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/EchoStubSettings.java
@@ -89,6 +89,7 @@
 import java.util.List;
 import java.util.Map;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -164,6 +165,7 @@
  *     .build();
  * }</pre>
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcComplianceCallableFactory.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcComplianceCallableFactory.java
index e61ad2900c52..6d6808165c3f 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcComplianceCallableFactory.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcComplianceCallableFactory.java
@@ -35,6 +35,7 @@
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -42,6 +43,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class GrpcComplianceCallableFactory implements GrpcStubCallableFactory {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcComplianceStub.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcComplianceStub.java
index 3949f8d8c968..1928846a7deb 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcComplianceStub.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcComplianceStub.java
@@ -45,6 +45,7 @@
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -52,6 +53,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class GrpcComplianceStub extends ComplianceStub {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcEchoCallableFactory.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcEchoCallableFactory.java
index 7c2726f06e18..efe6fabc1b41 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcEchoCallableFactory.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcEchoCallableFactory.java
@@ -35,6 +35,7 @@
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -42,6 +43,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class GrpcEchoCallableFactory implements GrpcStubCallableFactory {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcEchoStub.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcEchoStub.java
index c5dccbe24562..c4f4b8f8a4ea 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcEchoStub.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcEchoStub.java
@@ -67,6 +67,7 @@
 import java.util.UUID;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -74,6 +75,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class GrpcEchoStub extends EchoStub {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcIdentityCallableFactory.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcIdentityCallableFactory.java
index e59799ce9a92..24cc588c0e6f 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcIdentityCallableFactory.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcIdentityCallableFactory.java
@@ -35,6 +35,7 @@
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -42,6 +43,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class GrpcIdentityCallableFactory implements GrpcStubCallableFactory {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcIdentityStub.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcIdentityStub.java
index 666ce88c52a8..d43e8521875b 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcIdentityStub.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcIdentityStub.java
@@ -50,6 +50,7 @@
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -57,6 +58,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class GrpcIdentityStub extends IdentityStub {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcMessagingCallableFactory.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcMessagingCallableFactory.java
index ceeab3d586cb..ddefa6b22d45 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcMessagingCallableFactory.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcMessagingCallableFactory.java
@@ -35,6 +35,7 @@
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -42,6 +43,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class GrpcMessagingCallableFactory implements GrpcStubCallableFactory {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcMessagingStub.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcMessagingStub.java
index 4d343ab1e319..548d8bb5228e 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcMessagingStub.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcMessagingStub.java
@@ -70,6 +70,7 @@
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -77,6 +78,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class GrpcMessagingStub extends MessagingStub {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcSequenceServiceCallableFactory.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcSequenceServiceCallableFactory.java
index 43291ed81f3b..5fe5e72a4797 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcSequenceServiceCallableFactory.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcSequenceServiceCallableFactory.java
@@ -35,6 +35,7 @@
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -42,6 +43,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class GrpcSequenceServiceCallableFactory implements GrpcStubCallableFactory {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcSequenceServiceStub.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcSequenceServiceStub.java
index 545208ea67a2..a2377beaa52b 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcSequenceServiceStub.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcSequenceServiceStub.java
@@ -54,6 +54,7 @@
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -61,6 +62,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class GrpcSequenceServiceStub extends SequenceServiceStub {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcTestingCallableFactory.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcTestingCallableFactory.java
index 9b99f011af42..a38aab562383 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcTestingCallableFactory.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcTestingCallableFactory.java
@@ -35,6 +35,7 @@
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -42,6 +43,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class GrpcTestingCallableFactory implements GrpcStubCallableFactory {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcTestingStub.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcTestingStub.java
index 6ceaa01ce751..ec383fccedf1 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcTestingStub.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/GrpcTestingStub.java
@@ -57,6 +57,7 @@
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -64,6 +65,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class GrpcTestingStub extends TestingStub {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonComplianceCallableFactory.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonComplianceCallableFactory.java
index ea3d3be7bcab..35e76136d119 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonComplianceCallableFactory.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonComplianceCallableFactory.java
@@ -33,6 +33,7 @@
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.longrunning.Operation;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -40,6 +41,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class HttpJsonComplianceCallableFactory
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonComplianceStub.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonComplianceStub.java
index 247f16c37da8..f2d56fbf8b0b 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonComplianceStub.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonComplianceStub.java
@@ -52,6 +52,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -59,6 +60,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class HttpJsonComplianceStub extends ComplianceStub {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonEchoCallableFactory.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonEchoCallableFactory.java
index 70b68fc24700..ead7a784ff31 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonEchoCallableFactory.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonEchoCallableFactory.java
@@ -33,6 +33,7 @@
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.longrunning.Operation;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -40,6 +41,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class HttpJsonEchoCallableFactory
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonEchoStub.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonEchoStub.java
index a0e5b55daccd..f1f490bea15b 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonEchoStub.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonEchoStub.java
@@ -78,6 +78,7 @@
 import java.util.UUID;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -85,6 +86,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class HttpJsonEchoStub extends EchoStub {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonIdentityCallableFactory.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonIdentityCallableFactory.java
index 5ea4ee07aa74..b712335a4966 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonIdentityCallableFactory.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonIdentityCallableFactory.java
@@ -33,6 +33,7 @@
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.longrunning.Operation;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -40,6 +41,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class HttpJsonIdentityCallableFactory
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonIdentityStub.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonIdentityStub.java
index c4c305e0527b..8c4fb935787c 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonIdentityStub.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonIdentityStub.java
@@ -57,6 +57,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -64,6 +65,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class HttpJsonIdentityStub extends IdentityStub {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonMessagingCallableFactory.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonMessagingCallableFactory.java
index 6e59fe4c6872..1fe00091d732 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonMessagingCallableFactory.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonMessagingCallableFactory.java
@@ -33,6 +33,7 @@
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.longrunning.Operation;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -40,6 +41,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class HttpJsonMessagingCallableFactory
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonMessagingStub.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonMessagingStub.java
index dda9ca23b58a..6aaad20e8459 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonMessagingStub.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonMessagingStub.java
@@ -81,6 +81,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -88,6 +89,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class HttpJsonMessagingStub extends MessagingStub {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonSequenceServiceCallableFactory.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonSequenceServiceCallableFactory.java
index 34dc970004dc..5c96c69502a6 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonSequenceServiceCallableFactory.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonSequenceServiceCallableFactory.java
@@ -33,6 +33,7 @@
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.longrunning.Operation;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -40,6 +41,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class HttpJsonSequenceServiceCallableFactory
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonSequenceServiceStub.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonSequenceServiceStub.java
index da7116caad45..8e40b5e32b09 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonSequenceServiceStub.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonSequenceServiceStub.java
@@ -61,6 +61,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -68,6 +69,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class HttpJsonSequenceServiceStub extends SequenceServiceStub {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonTestingCallableFactory.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonTestingCallableFactory.java
index be1186b7ec97..21e3c14b566b 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonTestingCallableFactory.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonTestingCallableFactory.java
@@ -33,6 +33,7 @@
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.longrunning.Operation;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -40,6 +41,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class HttpJsonTestingCallableFactory
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonTestingStub.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonTestingStub.java
index ed6aeae3eb08..fdbff5f71a25 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonTestingStub.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/HttpJsonTestingStub.java
@@ -64,6 +64,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -71,6 +72,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class HttpJsonTestingStub extends TestingStub {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/IdentityStub.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/IdentityStub.java
index 740a6f42b3e8..62b7315c6aad 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/IdentityStub.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/IdentityStub.java
@@ -40,6 +40,7 @@
 import com.google.showcase.v1beta1.UpdateUserRequest;
 import com.google.showcase.v1beta1.User;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -47,6 +48,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public abstract class IdentityStub implements BackgroundResource {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/IdentityStubSettings.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/IdentityStubSettings.java
index c1163fe00050..bd1b8ac22d6a 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/IdentityStubSettings.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/IdentityStubSettings.java
@@ -71,6 +71,7 @@
 import java.time.Duration;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -121,6 +122,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/MessagingStub.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/MessagingStub.java
index 6bdad6e3354c..370965e9c472 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/MessagingStub.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/MessagingStub.java
@@ -61,6 +61,7 @@
 import com.google.showcase.v1beta1.UpdateBlurbRequest;
 import com.google.showcase.v1beta1.UpdateRoomRequest;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -68,6 +69,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public abstract class MessagingStub implements BackgroundResource {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/MessagingStubSettings.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/MessagingStubSettings.java
index 14f9ba167b58..63524a233b17 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/MessagingStubSettings.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/MessagingStubSettings.java
@@ -93,6 +93,7 @@
 import java.time.Duration;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -168,6 +169,7 @@
  *     .build();
  * }</pre>
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/SequenceServiceStub.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/SequenceServiceStub.java
index 39f8ccd1fc5e..d92c4203b486 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/SequenceServiceStub.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/SequenceServiceStub.java
@@ -44,6 +44,7 @@
 import com.google.showcase.v1beta1.StreamingSequence;
 import com.google.showcase.v1beta1.StreamingSequenceReport;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -51,6 +52,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public abstract class SequenceServiceStub implements BackgroundResource {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/SequenceServiceStubSettings.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/SequenceServiceStubSettings.java
index bbc13d23dc87..8e63e65c67b8 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/SequenceServiceStubSettings.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/SequenceServiceStubSettings.java
@@ -75,6 +75,7 @@
 import java.time.Duration;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -126,6 +127,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/TestingStub.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/TestingStub.java
index 92b4a42f59ad..f6ffe32525f8 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/TestingStub.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/TestingStub.java
@@ -47,6 +47,7 @@
 import com.google.showcase.v1beta1.VerifyTestRequest;
 import com.google.showcase.v1beta1.VerifyTestResponse;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -54,6 +55,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public abstract class TestingStub implements BackgroundResource {
diff --git a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/TestingStubSettings.java b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/TestingStubSettings.java
index 02d1260a2f83..da278f791454 100644
--- a/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/TestingStubSettings.java
+++ b/java-showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/TestingStubSettings.java
@@ -78,6 +78,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -128,6 +129,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
diff --git a/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/BlurbName.java b/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/BlurbName.java
index c0f03fe0caca..2e44117605ba 100644
--- a/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/BlurbName.java
+++ b/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/BlurbName.java
@@ -26,8 +26,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class BlurbName implements ResourceName {
   private static final PathTemplate USER_LEGACY_USER_BLURB =
diff --git a/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/ProfileName.java b/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/ProfileName.java
index 1a76331959b4..ee06ebfc70ff 100644
--- a/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/ProfileName.java
+++ b/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/ProfileName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class ProfileName implements ResourceName {
   private static final PathTemplate USER =
diff --git a/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/RoomName.java b/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/RoomName.java
index 1dbb32e73c7e..1370b309df9a 100644
--- a/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/RoomName.java
+++ b/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/RoomName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class RoomName implements ResourceName {
   private static final PathTemplate ROOM = PathTemplate.createWithoutUrlEncoding("rooms/{room}");
diff --git a/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/SequenceName.java b/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/SequenceName.java
index a4703d1b3983..81b4e7bd25d4 100644
--- a/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/SequenceName.java
+++ b/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/SequenceName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class SequenceName implements ResourceName {
   private static final PathTemplate SEQUENCE =
diff --git a/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/SequenceReportName.java b/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/SequenceReportName.java
index 27970631de56..16898ca82d83 100644
--- a/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/SequenceReportName.java
+++ b/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/SequenceReportName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class SequenceReportName implements ResourceName {
   private static final PathTemplate SEQUENCE =
diff --git a/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/SessionName.java b/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/SessionName.java
index 4f40865d28d0..883685a36c55 100644
--- a/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/SessionName.java
+++ b/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/SessionName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class SessionName implements ResourceName {
   private static final PathTemplate SESSION =
diff --git a/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/StreamingSequenceName.java b/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/StreamingSequenceName.java
index bfced7876efc..e87564212f17 100644
--- a/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/StreamingSequenceName.java
+++ b/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/StreamingSequenceName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class StreamingSequenceName implements ResourceName {
   private static final PathTemplate STREAMING_SEQUENCE =
diff --git a/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/StreamingSequenceReportName.java b/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/StreamingSequenceReportName.java
index 59f40f2c589f..ea6ae25d25b0 100644
--- a/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/StreamingSequenceReportName.java
+++ b/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/StreamingSequenceReportName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class StreamingSequenceReportName implements ResourceName {
   private static final PathTemplate STREAMING_SEQUENCE =
diff --git a/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/TestName.java b/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/TestName.java
index 34499c19fda5..c8b6ed227aff 100644
--- a/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/TestName.java
+++ b/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/TestName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class TestName implements ResourceName {
   private static final PathTemplate SESSION_TEST =
diff --git a/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/UserName.java b/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/UserName.java
index 92105d5d7753..7a9020f92bd9 100644
--- a/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/UserName.java
+++ b/java-showcase/proto-gapic-showcase-v1beta1/src/main/java/com/google/showcase/v1beta1/UserName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class UserName implements ResourceName {
   private static final PathTemplate USER = PathTemplate.createWithoutUrlEncoding("users/{user}");
diff --git a/rules_java_gapic/java_gapic.bzl b/rules_java_gapic/java_gapic.bzl
index 0eaf06264f66..6b778feca354 100644
--- a/rules_java_gapic/java_gapic.bzl
+++ b/rules_java_gapic/java_gapic.bzl
@@ -288,6 +288,7 @@ def java_gapic_library(
             "@com_google_api_api_common//jar",
             "@com_google_guava_guava//jar",
             "@javax_annotation_javax_annotation_api//jar",
+            "@org_jspecify_jspecify//jar",
         ],
         **kwargs
     )
@@ -307,6 +308,7 @@ def java_gapic_library(
         "@com_google_auth_google_auth_library_oauth2_http//jar",
         "@com_google_http_client_google_http_client//jar",
         "@javax_annotation_javax_annotation_api//jar",
+        "@org_jspecify_jspecify//jar",
     ]
 
     if not transport or transport == "grpc":
diff --git a/sdk-platform-java/gapic-generator-java/pom.xml b/sdk-platform-java/gapic-generator-java/pom.xml
index 736b3ca5a20e..ac9a2a948e24 100644
--- a/sdk-platform-java/gapic-generator-java/pom.xml
+++ b/sdk-platform-java/gapic-generator-java/pom.xml
@@ -283,6 +283,11 @@
   </build>
 
   <dependencies>
+    <dependency>
+      <groupId>org.jspecify</groupId>
+      <artifactId>jspecify</artifactId>
+      <version>${jspecify.version}</version>
+    </dependency>
     <dependency>
       <groupId>com.google.guava</groupId>
       <artifactId>guava</artifactId>
diff --git a/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractServiceCallableFactoryClassComposer.java b/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractServiceCallableFactoryClassComposer.java
index fd861390a7ee..066c55383c0b 100644
--- a/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractServiceCallableFactoryClassComposer.java
+++ b/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractServiceCallableFactoryClassComposer.java
@@ -48,6 +48,7 @@
 import java.util.List;
 import java.util.stream.Collectors;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 public abstract class AbstractServiceCallableFactoryClassComposer implements ClassComposer {
   private final TransportContext transportContext;
@@ -93,6 +94,7 @@ public GapicClass generate(GapicContext context, Service service) {
 
   protected List<AnnotationNode> createClassAnnotations(Service service, TypeStore typeStore) {
     List<AnnotationNode> annotations = new ArrayList<>();
+    annotations.add(AnnotationNode.withType(typeStore.get("NullMarked")));
     if (!PackageChecker.isGaApi(service.pakkage())) {
       annotations.add(AnnotationNode.withType(typeStore.get("BetaApi")));
     }
@@ -349,7 +351,8 @@ private TypeStore createTypes(Service service) {
             UnaryCallSettings.class,
             UnaryCallable.class,
             Generated.class,
-            UnsupportedOperationException.class);
+            UnsupportedOperationException.class,
+            NullMarked.class);
     return new TypeStore(concreteClazzes);
   }
 }
diff --git a/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractServiceClientClassComposer.java b/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractServiceClientClassComposer.java
index 913ffd0f5c75..42c7bd743fe4 100644
--- a/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractServiceClientClassComposer.java
+++ b/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractServiceClientClassComposer.java
@@ -103,6 +103,7 @@
 import java.util.function.Function;
 import java.util.stream.Collectors;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 public abstract class AbstractServiceClientClassComposer implements ClassComposer {
   private static final String CALLABLE_NAME_PATTERN = "%sCallable";
@@ -193,6 +194,7 @@ public GapicClass generate(GapicContext context, Service service) {
 
   private static List<AnnotationNode> createClassAnnotations(Service service, TypeStore typeStore) {
     List<AnnotationNode> annotations = new ArrayList<>();
+    annotations.add(AnnotationNode.withType(typeStore.get("NullMarked")));
     if (!PackageChecker.isGaApi(service.pakkage())) {
       annotations.add(AnnotationNode.withType(typeStore.get("BetaApi")));
     }
@@ -1786,6 +1788,7 @@ private static TypeStore createTypes(Service service, Map<String, Message> messa
             InterruptedException.class,
             IOException.class,
             MoreExecutors.class,
+            NullMarked.class,
             Objects.class,
             Operation.class,
             OperationFuture.class,
diff --git a/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractServiceSettingsClassComposer.java b/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractServiceSettingsClassComposer.java
index e117097b1094..d7241886efc8 100644
--- a/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractServiceSettingsClassComposer.java
+++ b/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractServiceSettingsClassComposer.java
@@ -79,6 +79,7 @@
 import java.util.function.Function;
 import java.util.stream.Collectors;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 public abstract class AbstractServiceSettingsClassComposer implements ClassComposer {
   private static final String BUILDER_CLASS_NAME = "Builder";
@@ -204,6 +205,7 @@ private static List<CommentStatement> createClassHeaderComments(
 
   private static List<AnnotationNode> createClassAnnotations(Service service) {
     List<AnnotationNode> annotations = new ArrayList<>();
+    annotations.add(AnnotationNode.withType(FIXED_TYPESTORE.get("NullMarked")));
     if (!PackageChecker.isGaApi(service.pakkage())) {
       annotations.add(AnnotationNode.withType(FIXED_TYPESTORE.get("BetaApi")));
     }
@@ -847,7 +849,8 @@ private static TypeStore createStaticTypes() {
             StreamingCallSettings.class,
             StubSettings.class,
             TransportChannelProvider.class,
-            UnaryCallSettings.class);
+            UnaryCallSettings.class,
+            NullMarked.class);
     return new TypeStore(concreteClazzes);
   }
 
diff --git a/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractServiceStubClassComposer.java b/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractServiceStubClassComposer.java
index 5cdb08ff1051..423a25eee11a 100644
--- a/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractServiceStubClassComposer.java
+++ b/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractServiceStubClassComposer.java
@@ -54,6 +54,7 @@
 import java.util.Map;
 import java.util.stream.Collectors;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 public abstract class AbstractServiceStubClassComposer implements ClassComposer {
 
@@ -93,6 +94,7 @@ public GapicClass generate(GapicContext context, Service service) {
 
   private static List<AnnotationNode> createClassAnnotations(Service service, TypeStore typeStore) {
     List<AnnotationNode> annotations = new ArrayList<>();
+    annotations.add(AnnotationNode.withType(typeStore.get("NullMarked")));
     if (!PackageChecker.isGaApi(service.pakkage())) {
       annotations.add(AnnotationNode.withType(typeStore.get("BetaApi")));
     }
@@ -270,7 +272,8 @@ private static TypeStore createTypes(Service service, Map<String, Message> messa
             OperationCallable.class,
             ServerStreamingCallable.class,
             UnaryCallable.class,
-            UnsupportedOperationException.class);
+            UnsupportedOperationException.class,
+            NullMarked.class);
     TypeStore typeStore = new TypeStore(concreteClazzes);
 
     typeStore.put("com.google.longrunning.stub", "OperationsStub");
diff --git a/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractServiceStubSettingsClassComposer.java b/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractServiceStubSettingsClassComposer.java
index 489e82f9d56e..9a0c1337b115 100644
--- a/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractServiceStubSettingsClassComposer.java
+++ b/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractServiceStubSettingsClassComposer.java
@@ -124,6 +124,7 @@
 import java.util.stream.Collectors;
 import javax.annotation.Generated;
 import javax.annotation.Nullable;
+import org.jspecify.annotations.NullMarked;
 
 public abstract class AbstractServiceStubSettingsClassComposer implements ClassComposer {
   private static final Statement EMPTY_LINE_STATEMENT = EmptyLineStatement.create();
@@ -411,6 +412,7 @@ protected MethodDefinition createApiClientHeaderProviderBuilderMethod(
 
   private List<AnnotationNode> createClassAnnotations(Service service) {
     List<AnnotationNode> annotations = new ArrayList<>();
+    annotations.add(AnnotationNode.withType(FIXED_TYPESTORE.get("NullMarked")));
     if (!PackageChecker.isGaApi(service.pakkage())) {
       annotations.add(AnnotationNode.withType(FIXED_TYPESTORE.get("BetaApi")));
     }
@@ -2217,7 +2219,8 @@ private static TypeStore createStaticTypes() {
             SuppressWarnings.class,
             TransportChannelProvider.class,
             UnaryCallSettings.class,
-            UnaryCallable.class);
+            UnaryCallable.class,
+            NullMarked.class);
     return new TypeStore(concreteClazzes);
   }
 
diff --git a/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractTransportServiceStubClassComposer.java b/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractTransportServiceStubClassComposer.java
index 922dda48dcc9..6cdf49e38d4c 100644
--- a/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractTransportServiceStubClassComposer.java
+++ b/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractTransportServiceStubClassComposer.java
@@ -100,6 +100,7 @@
 import java.util.stream.Collectors;
 import javax.annotation.Generated;
 import javax.annotation.Nullable;
+import org.jspecify.annotations.NullMarked;
 
 public abstract class AbstractTransportServiceStubClassComposer implements ClassComposer {
   private static final List<String> AIP_STANDARDS_METHODS =
@@ -152,7 +153,8 @@ private static TypeStore createStaticTypes() {
             TimeUnit.class,
             TypeRegistry.class,
             UnaryCallable.class,
-            UnsupportedOperationException.class);
+            UnsupportedOperationException.class,
+            NullMarked.class);
     return new TypeStore(concreteClazzes);
   }
 
@@ -548,6 +550,7 @@ private VariableExpr getOperationCallableExpr(Method protoMethod, String callabl
 
   protected List<AnnotationNode> createClassAnnotations(Service service) {
     List<AnnotationNode> annotations = new ArrayList<>();
+    annotations.add(AnnotationNode.withType(FIXED_TYPESTORE.get("NullMarked")));
     if (!PackageChecker.isGaApi(service.pakkage())) {
       annotations.add(AnnotationNode.withType(FIXED_TYPESTORE.get("BetaApi")));
     }
diff --git a/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/resourcename/ResourceNameHelperClassComposer.java b/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/resourcename/ResourceNameHelperClassComposer.java
index 775a88c01b13..69f9ca96e0f9 100644
--- a/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/resourcename/ResourceNameHelperClassComposer.java
+++ b/sdk-platform-java/gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/resourcename/ResourceNameHelperClassComposer.java
@@ -69,6 +69,7 @@
 import java.util.function.Function;
 import java.util.stream.Collectors;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 public class ResourceNameHelperClassComposer {
   private static final String CLASS_NAME_PATTERN = "%sName";
@@ -152,6 +153,7 @@ public GapicClass generate(ResourceName resourceName, GapicContext context) {
 
   private static List<AnnotationNode> createClassAnnotations() {
     return Arrays.asList(
+        AnnotationNode.withType(FIXED_TYPESTORE.get("NullMarked")),
         AnnotationNode.builder()
             .setType(FIXED_TYPESTORE.get("Generated"))
             .setDescription("by gapic-generator-java")
@@ -1704,7 +1706,8 @@ private static TypeStore createStaticTypes() {
             PathTemplate.class,
             Preconditions.class,
             com.google.api.resourcenames.ResourceName.class,
-            ValidationException.class);
+            ValidationException.class,
+            NullMarked.class);
     return new TypeStore(concreteClazzes);
   }
 
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/engine/writer/goldens/GrpcServiceClientWithNestedClassImport.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/engine/writer/goldens/GrpcServiceClientWithNestedClassImport.golden
index 9a8f46553d49..c5edba8acd9a 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/engine/writer/goldens/GrpcServiceClientWithNestedClassImport.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/engine/writer/goldens/GrpcServiceClientWithNestedClassImport.golden
@@ -8,6 +8,7 @@ import com.google.types.testing.stub.NestedMessageServiceStubSettings;
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -95,6 +96,7 @@ import javax.annotation.Generated;
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class NestedMessageServiceClient implements BackgroundResource {
   private final NestedMessageServiceSettings settings;
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/ApiVersionTestingStubSettings.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/ApiVersionTestingStubSettings.golden
index 86eb85a24497..7b37b4120ddb 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/ApiVersionTestingStubSettings.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/ApiVersionTestingStubSettings.golden
@@ -25,6 +25,7 @@ import com.google.common.collect.Lists;
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -76,6 +77,7 @@ import javax.annotation.Generated;
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
 public class EchoWithVersionStubSettings extends StubSettings<EchoWithVersionStubSettings> {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/BookshopClient.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/BookshopClient.golden
index 13e54850392c..d093dec5b5a5 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/BookshopClient.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/BookshopClient.golden
@@ -9,6 +9,7 @@ import java.io.IOException;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -98,6 +99,7 @@ import javax.annotation.Generated;
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class BookshopClient implements BackgroundResource {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/DeprecatedServiceClient.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/DeprecatedServiceClient.golden
index aec12869e407..5afedc72d093 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/DeprecatedServiceClient.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/DeprecatedServiceClient.golden
@@ -8,6 +8,7 @@ import com.google.testdata.v1.stub.DeprecatedServiceStubSettings;
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -110,6 +111,7 @@ import javax.annotation.Generated;
  *
  * @deprecated This class is deprecated and will be removed in the next major version update.
  */
+@NullMarked
 @Deprecated
 @Generated("by gapic-generator-java")
 public class DeprecatedServiceClient implements BackgroundResource {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/DeprecatedServiceSettings.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/DeprecatedServiceSettings.golden
index 3a17bc1a9b64..2f2222d4979b 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/DeprecatedServiceSettings.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/DeprecatedServiceSettings.golden
@@ -15,6 +15,7 @@ import com.google.testdata.v1.stub.DeprecatedServiceStubSettings;
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -68,6 +69,7 @@ import javax.annotation.Generated;
  *
  * @deprecated This class is deprecated and will be removed in the next major version update.
  */
+@NullMarked
 @Deprecated
 @Generated("by gapic-generator-java")
 public class DeprecatedServiceSettings extends ClientSettings<DeprecatedServiceSettings> {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/DeprecatedServiceStub.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/DeprecatedServiceStub.golden
index 6a40197ba46c..9b25100eb162 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/DeprecatedServiceStub.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/DeprecatedServiceStub.golden
@@ -5,6 +5,7 @@ import com.google.api.gax.rpc.UnaryCallable;
 import com.google.protobuf.Empty;
 import com.google.testdata.v1.FibonacciRequest;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -14,6 +15,7 @@ import javax.annotation.Generated;
  *
  * @deprecated This class is deprecated and will be removed in the next major version update.
  */
+@NullMarked
 @Deprecated
 @Generated("by gapic-generator-java")
 public abstract class DeprecatedServiceStub implements BackgroundResource {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/DeprecatedServiceStubSettings.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/DeprecatedServiceStubSettings.golden
index b33cacc753fc..51d610d81f0d 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/DeprecatedServiceStubSettings.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/DeprecatedServiceStubSettings.golden
@@ -26,6 +26,7 @@ import java.io.IOException;
 import java.time.Duration;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -80,6 +81,7 @@ import javax.annotation.Generated;
  *
  * @deprecated This class is deprecated and will be removed in the next major version update.
  */
+@NullMarked
 @Deprecated
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoClient.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoClient.golden
index 612111aea0df..153bc625a8c3 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoClient.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoClient.golden
@@ -27,6 +27,7 @@ import java.io.IOException;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -260,6 +261,7 @@ import javax.annotation.Generated;
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class EchoClient implements BackgroundResource {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoServiceSelectiveGapicClient.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoServiceSelectiveGapicClient.golden
index 731ebe1834bf..7c2bf556b96d 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoServiceSelectiveGapicClient.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoServiceSelectiveGapicClient.golden
@@ -10,6 +10,7 @@ import com.google.selective.generate.v1beta1.stub.EchoServiceShouldGenerateParti
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -155,6 +156,7 @@ import javax.annotation.Generated;
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class EchoServiceShouldGeneratePartialUsualClient implements BackgroundResource {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoServiceSelectiveGapicClientStub.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoServiceSelectiveGapicClientStub.golden
index d654e9644c93..c5ff4c5e86e8 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoServiceSelectiveGapicClientStub.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoServiceSelectiveGapicClientStub.golden
@@ -8,6 +8,7 @@ import com.google.api.gax.rpc.UnaryCallable;
 import com.google.selective.generate.v1beta1.EchoRequest;
 import com.google.selective.generate.v1beta1.EchoResponse;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -15,6 +16,7 @@ import javax.annotation.Generated;
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public abstract class EchoServiceShouldGeneratePartialUsualStub implements BackgroundResource {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoServiceSelectiveGapicServiceSettings.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoServiceSelectiveGapicServiceSettings.golden
index e78f11aef44b..ddb91ae8bcbb 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoServiceSelectiveGapicServiceSettings.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoServiceSelectiveGapicServiceSettings.golden
@@ -17,6 +17,7 @@ import com.google.selective.generate.v1beta1.stub.EchoServiceShouldGenerateParti
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -70,6 +71,7 @@ import javax.annotation.Generated;
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class EchoServiceShouldGeneratePartialUsualSettings
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoServiceSelectiveGapicStubSettings.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoServiceSelectiveGapicStubSettings.golden
index 8e4331441cc1..5c171f04360a 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoServiceSelectiveGapicStubSettings.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoServiceSelectiveGapicStubSettings.golden
@@ -28,6 +28,7 @@ import com.google.selective.generate.v1beta1.EchoResponse;
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -82,6 +83,7 @@ import javax.annotation.Generated;
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoSettings.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoSettings.golden
index 753662f8f99e..a9770bf54cd4 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoSettings.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoSettings.golden
@@ -23,6 +23,7 @@ import com.google.showcase.v1beta1.stub.EchoStubSettings;
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -98,6 +99,7 @@ import javax.annotation.Generated;
  *     .build();
  * }</pre>
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class EchoSettings extends ClientSettings<EchoSettings> {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoStub.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoStub.golden
index c43465da6889..8fed4fe54d48 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoStub.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoStub.golden
@@ -25,6 +25,7 @@ import com.google.showcase.v1beta1.WaitMetadata;
 import com.google.showcase.v1beta1.WaitRequest;
 import com.google.showcase.v1beta1.WaitResponse;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -32,6 +33,7 @@ import javax.annotation.Generated;
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public abstract class EchoStub implements BackgroundResource {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoStubSettings.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoStubSettings.golden
index 837e9e6b2933..6713de000399 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoStubSettings.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/EchoStubSettings.golden
@@ -54,6 +54,7 @@ import java.io.IOException;
 import java.time.Duration;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -129,6 +130,7 @@ import javax.annotation.Generated;
  *     .build();
  * }</pre>
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcAutoPopulateFieldStub.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcAutoPopulateFieldStub.golden
index f3614d7226ee..b7270cd7441f 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcAutoPopulateFieldStub.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcAutoPopulateFieldStub.golden
@@ -20,6 +20,7 @@ import java.io.IOException;
 import java.util.UUID;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -27,6 +28,7 @@ import javax.annotation.Generated;
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcAutoPopulateFieldTestingStub extends AutoPopulateFieldTestingStub {
   private static final MethodDescriptor<
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcBigQueryJobServiceStub.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcBigQueryJobServiceStub.golden
index a6a08d1acba6..05a69268c60a 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcBigQueryJobServiceStub.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcBigQueryJobServiceStub.golden
@@ -18,6 +18,7 @@ import java.io.IOException;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -25,6 +26,7 @@ import javax.annotation.Generated;
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcJobServiceStub extends JobServiceStub {
   private static final MethodDescriptor<JobProto.DeleteJobRequest, Empty>
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcCallableNameTypeStub.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcCallableNameTypeStub.golden
index 870c0181d1cd..d2f843a3b4d8 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcCallableNameTypeStub.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcCallableNameTypeStub.golden
@@ -16,6 +16,7 @@ import java.io.IOException;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -23,6 +24,7 @@ import javax.annotation.Generated;
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcCallableNameTypeServiceStub extends CallableNameTypeServiceStub {
   private static final MethodDescriptor<GetApiOperationRequest, ApiOperation>
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcDeprecatedServiceCallableFactory.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcDeprecatedServiceCallableFactory.golden
index c27b65e6ae5c..1b15b2753641 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcDeprecatedServiceCallableFactory.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcDeprecatedServiceCallableFactory.golden
@@ -18,6 +18,7 @@ import com.google.api.gax.rpc.UnaryCallable;
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -27,6 +28,7 @@ import javax.annotation.Generated;
  *
  * @deprecated This class is deprecated and will be removed in the next major version update.
  */
+@NullMarked
 @Deprecated
 @Generated("by gapic-generator-java")
 public class GrpcDeprecatedServiceCallableFactory implements GrpcStubCallableFactory {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcDeprecatedServiceStub.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcDeprecatedServiceStub.golden
index c225eb1a32f1..f0e3fcb15f1a 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcDeprecatedServiceStub.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcDeprecatedServiceStub.golden
@@ -14,6 +14,7 @@ import io.grpc.protobuf.ProtoUtils;
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -23,6 +24,7 @@ import javax.annotation.Generated;
  *
  * @deprecated This class is deprecated and will be removed in the next major version update.
  */
+@NullMarked
 @Deprecated
 @Generated("by gapic-generator-java")
 public class GrpcDeprecatedServiceStub extends DeprecatedServiceStub {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcEchoCallableFactory.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcEchoCallableFactory.golden
index d6ac9c9fe7dc..946d23dd9c79 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcEchoCallableFactory.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcEchoCallableFactory.golden
@@ -19,6 +19,7 @@ import com.google.api.gax.rpc.UnaryCallable;
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -26,6 +27,7 @@ import javax.annotation.Generated;
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class GrpcEchoCallableFactory implements GrpcStubCallableFactory {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcEchoStub.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcEchoStub.golden
index 6b6bf6368139..b00e38a732d4 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcEchoStub.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcEchoStub.golden
@@ -33,6 +33,7 @@ import io.grpc.protobuf.ProtoUtils;
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -40,6 +41,7 @@ import javax.annotation.Generated;
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class GrpcEchoStub extends EchoStub {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcLoggingStub.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcLoggingStub.golden
index 940d0c779aec..641885e7c64b 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcLoggingStub.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcLoggingStub.golden
@@ -31,6 +31,7 @@ import java.io.IOException;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -38,6 +39,7 @@ import javax.annotation.Generated;
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcLoggingServiceV2Stub extends LoggingServiceV2Stub {
   private static final MethodDescriptor<DeleteLogRequest, Empty> deleteLogMethodDescriptor =
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcPublisherStub.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcPublisherStub.golden
index a881a35e880e..315dc7a25734 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcPublisherStub.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcPublisherStub.golden
@@ -33,6 +33,7 @@ import java.io.IOException;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -40,6 +41,7 @@ import javax.annotation.Generated;
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcPublisherStub extends PublisherStub {
   private static final MethodDescriptor<Topic, Topic> createTopicMethodDescriptor =
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcResourceNameExtractorStub.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcResourceNameExtractorStub.golden
index 4657fbe7da7d..fad7579a00ee 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcResourceNameExtractorStub.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcResourceNameExtractorStub.golden
@@ -29,6 +29,7 @@ import java.util.HashMap;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -36,6 +37,7 @@ import javax.annotation.Generated;
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcResourceNameExtractorTestingStub extends ResourceNameExtractorTestingStub {
   private static final MethodDescriptor<GetFooRequest, Foo> getFooMethodDescriptor =
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcRoutingHeadersStub.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcRoutingHeadersStub.golden
index 26b66097b557..2de1cb9cc9c9 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcRoutingHeadersStub.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcRoutingHeadersStub.golden
@@ -20,6 +20,7 @@ import java.io.IOException;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -27,6 +28,7 @@ import javax.annotation.Generated;
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcExplicitDynamicRoutingHeaderTestingStub
     extends ExplicitDynamicRoutingHeaderTestingStub {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcTestingStub.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcTestingStub.golden
index a467bb696fa9..d01d58872b0a 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcTestingStub.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/GrpcTestingStub.golden
@@ -35,6 +35,7 @@ import java.io.IOException;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -42,6 +43,7 @@ import javax.annotation.Generated;
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class GrpcTestingStub extends TestingStub {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/IdentityClient.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/IdentityClient.golden
index efb41dc308f5..1f6390842460 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/IdentityClient.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/IdentityClient.golden
@@ -17,6 +17,7 @@ import java.io.IOException;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -175,6 +176,7 @@ import javax.annotation.Generated;
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class IdentityClient implements BackgroundResource {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/JobServiceStubSettings.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/JobServiceStubSettings.golden
index 89ddd1d70399..6ec8f16f177c 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/JobServiceStubSettings.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/JobServiceStubSettings.golden
@@ -36,6 +36,7 @@ import java.io.IOException;
 import java.time.Duration;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -86,6 +87,7 @@ import javax.annotation.Generated;
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
 public class JobServiceStubSettings extends StubSettings<JobServiceStubSettings> {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/LoggingServiceV2StubSettings.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/LoggingServiceV2StubSettings.golden
index d3b2ed5a616b..213edf6a3d4b 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/LoggingServiceV2StubSettings.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/LoggingServiceV2StubSettings.golden
@@ -59,6 +59,7 @@ import java.time.Duration;
 import java.util.Collection;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -110,6 +111,7 @@ import javax.annotation.Generated;
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
 public class LoggingServiceV2StubSettings extends StubSettings<LoggingServiceV2StubSettings> {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/MessagingClient.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/MessagingClient.golden
index 359ba586244e..f53d16b8b749 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/MessagingClient.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/MessagingClient.golden
@@ -25,6 +25,7 @@ import java.io.IOException;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -325,6 +326,7 @@ import javax.annotation.Generated;
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class MessagingClient implements BackgroundResource {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/PublisherStubSettings.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/PublisherStubSettings.golden
index 1c48ebf05afe..5dd715e05b8f 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/PublisherStubSettings.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/PublisherStubSettings.golden
@@ -60,6 +60,7 @@ import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -110,6 +111,7 @@ import javax.annotation.Generated;
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
 public class PublisherStubSettings extends StubSettings<PublisherStubSettings> {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/EchoClient.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/EchoClient.golden
index 91e167d4e103..35c02eda2d66 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/EchoClient.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/EchoClient.golden
@@ -27,6 +27,7 @@ import java.io.IOException;
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -282,6 +283,7 @@ import javax.annotation.Generated;
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class EchoClient implements BackgroundResource {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/EchoSettings.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/EchoSettings.golden
index 2249b438e52b..12383ffd66c1 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/EchoSettings.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/EchoSettings.golden
@@ -24,6 +24,7 @@ import com.google.showcase.grpcrest.v1beta1.stub.EchoStubSettings;
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -99,6 +100,7 @@ import javax.annotation.Generated;
  *     .build();
  * }</pre>
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class EchoSettings extends ClientSettings<EchoSettings> {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/EchoStubSettings.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/EchoStubSettings.golden
index 3ca91988a4bd..e29f91480185 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/EchoStubSettings.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/EchoStubSettings.golden
@@ -58,6 +58,7 @@ import java.io.IOException;
 import java.time.Duration;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -133,6 +134,7 @@ import javax.annotation.Generated;
  *     .build();
  * }</pre>
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/GrpcEchoCallableFactory.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/GrpcEchoCallableFactory.golden
index 99bb5884092a..280c988aca17 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/GrpcEchoCallableFactory.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/GrpcEchoCallableFactory.golden
@@ -19,6 +19,7 @@ import com.google.api.gax.rpc.UnaryCallable;
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -26,6 +27,7 @@ import javax.annotation.Generated;
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class GrpcEchoCallableFactory implements GrpcStubCallableFactory {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/GrpcEchoStub.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/GrpcEchoStub.golden
index 3d337d1d4459..880d307e9a14 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/GrpcEchoStub.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/GrpcEchoStub.golden
@@ -35,6 +35,7 @@ import java.io.IOException;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -42,6 +43,7 @@ import javax.annotation.Generated;
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class GrpcEchoStub extends EchoStub {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/GrpcWickedCallableFactory.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/GrpcWickedCallableFactory.golden
index 88f063999a44..b94ed408707d 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/GrpcWickedCallableFactory.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/GrpcWickedCallableFactory.golden
@@ -19,6 +19,7 @@ import com.google.api.gax.rpc.UnaryCallable;
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -26,6 +27,7 @@ import javax.annotation.Generated;
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class GrpcWickedCallableFactory implements GrpcStubCallableFactory {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/GrpcWickedStub.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/GrpcWickedStub.golden
index c421c2a8a698..b0ffc0fa206a 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/GrpcWickedStub.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/GrpcWickedStub.golden
@@ -17,6 +17,7 @@ import io.grpc.protobuf.ProtoUtils;
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -24,6 +25,7 @@ import javax.annotation.Generated;
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class GrpcWickedStub extends WickedStub {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/HttpJsonEchoCallableFactory.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/HttpJsonEchoCallableFactory.golden
index 5da8337d63b0..cc730b52f6e7 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/HttpJsonEchoCallableFactory.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/HttpJsonEchoCallableFactory.golden
@@ -17,6 +17,7 @@ import com.google.api.gax.rpc.UnaryCallSettings;
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.longrunning.Operation;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -24,6 +25,7 @@ import javax.annotation.Generated;
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class HttpJsonEchoCallableFactory
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/HttpJsonEchoStub.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/HttpJsonEchoStub.golden
index 1ca61a984099..c66fb1e95232 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/HttpJsonEchoStub.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/HttpJsonEchoStub.golden
@@ -46,6 +46,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -53,6 +54,7 @@ import javax.annotation.Generated;
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class HttpJsonEchoStub extends EchoStub {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/WickedClient.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/WickedClient.golden
index 138bee4bc15d..fff1e0377a22 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/WickedClient.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/WickedClient.golden
@@ -10,6 +10,7 @@ import com.google.showcase.v1beta1.stub.WickedStubSettings;
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -113,6 +114,7 @@ import javax.annotation.Generated;
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class WickedClient implements BackgroundResource {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/WickedSettings.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/WickedSettings.golden
index 7df7e658dce4..95f2e533d03d 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/WickedSettings.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/WickedSettings.golden
@@ -16,6 +16,7 @@ import com.google.showcase.v1beta1.stub.WickedStubSettings;
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -66,6 +67,7 @@ import javax.annotation.Generated;
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class WickedSettings extends ClientSettings<WickedSettings> {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/WickedStubSettings.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/WickedStubSettings.golden
index e84994274db9..4a1bc0d0ea14 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/WickedStubSettings.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/WickedStubSettings.golden
@@ -27,6 +27,7 @@ import com.google.showcase.v1beta1.EvilResponse;
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -77,6 +78,7 @@ import javax.annotation.Generated;
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/resourcename/goldens/AgentName.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/resourcename/goldens/AgentName.golden
index 2eb43f4f3964..a35217c08a0a 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/resourcename/goldens/AgentName.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/resourcename/goldens/AgentName.golden
@@ -10,8 +10,10 @@ import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class AgentName implements ResourceName {
   private static final PathTemplate PROJECT_LOCATION =
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/resourcename/goldens/BillingAccountLocationName.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/resourcename/goldens/BillingAccountLocationName.golden
index 123088ef24e8..bf9b58f73ed0 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/resourcename/goldens/BillingAccountLocationName.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/resourcename/goldens/BillingAccountLocationName.golden
@@ -9,8 +9,10 @@ import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class BillingAccountLocationName implements ResourceName {
   private static final PathTemplate BILLING_ACCOUNT_LOCATION =
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/resourcename/goldens/CollisionResourceName.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/resourcename/goldens/CollisionResourceName.golden
index 273db9bd662f..515dc35aead2 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/resourcename/goldens/CollisionResourceName.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/resourcename/goldens/CollisionResourceName.golden
@@ -8,8 +8,10 @@ import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class ResourceName implements com.google.api.resourcenames.ResourceName {
   private static final PathTemplate PROJECT_LOCATION_DEPLOYMENT_REVISION_RESOURCE =
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/resourcename/goldens/FoobarName.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/resourcename/goldens/FoobarName.golden
index 4dcf36186aad..c9e2d43c6959 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/resourcename/goldens/FoobarName.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/resourcename/goldens/FoobarName.golden
@@ -10,8 +10,10 @@ import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class FoobarName implements ResourceName {
   private static final PathTemplate PROJECT_FOOBAR =
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/resourcename/goldens/SessionName.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/resourcename/goldens/SessionName.golden
index cb5996f0ed1b..f5c711d82aa2 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/resourcename/goldens/SessionName.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/resourcename/goldens/SessionName.golden
@@ -9,8 +9,10 @@ import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class SessionName implements ResourceName {
   private static final PathTemplate SESSION =
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/resourcename/goldens/TestName.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/resourcename/goldens/TestName.golden
index 0fc68b527a3a..571aec00ec5f 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/resourcename/goldens/TestName.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/resourcename/goldens/TestName.golden
@@ -9,8 +9,10 @@ import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class TestName implements ResourceName {
   private static final PathTemplate SESSION_SHARD_ID_TEST_ID =
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/ComplianceSettings.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/ComplianceSettings.golden
index 9c210dc69564..1d554dc788b6 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/ComplianceSettings.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/ComplianceSettings.golden
@@ -15,6 +15,7 @@ import com.google.showcase.v1beta1.stub.ComplianceStubSettings;
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -65,6 +66,7 @@ import javax.annotation.Generated;
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class ComplianceSettings extends ClientSettings<ComplianceSettings> {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/ComplianceStubSettings.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/ComplianceStubSettings.golden
index f4c6b636af62..db257e4d5a3d 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/ComplianceStubSettings.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/ComplianceStubSettings.golden
@@ -29,6 +29,7 @@ import com.google.showcase.v1beta1.RepeatResponse;
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -79,6 +80,7 @@ import javax.annotation.Generated;
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonApiVersionTestingStubSettings.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonApiVersionTestingStubSettings.golden
index 924e9c556626..8b0b94e4daab 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonApiVersionTestingStubSettings.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonApiVersionTestingStubSettings.golden
@@ -25,6 +25,7 @@ import com.google.common.collect.Lists;
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -76,6 +77,7 @@ import javax.annotation.Generated;
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
 public class EchoWithVersionStubSettings extends StubSettings<EchoWithVersionStubSettings> {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonAutoPopulateFieldTestingStub.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonAutoPopulateFieldTestingStub.golden
index 6b390feb69b0..00c0e65f570b 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonAutoPopulateFieldTestingStub.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonAutoPopulateFieldTestingStub.golden
@@ -27,6 +27,7 @@ import java.util.Map;
 import java.util.UUID;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -34,6 +35,7 @@ import javax.annotation.Generated;
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class HttpJsonAutoPopulateFieldTestingStub extends AutoPopulateFieldTestingStub {
   private static final TypeRegistry typeRegistry = TypeRegistry.newBuilder().build();
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonComplianceCallableFactory.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonComplianceCallableFactory.golden
index 25f9086a1308..9caec1171e0e 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonComplianceCallableFactory.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonComplianceCallableFactory.golden
@@ -17,6 +17,7 @@ import com.google.api.gax.rpc.UnaryCallSettings;
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.longrunning.Operation;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -24,6 +25,7 @@ import javax.annotation.Generated;
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class HttpJsonComplianceCallableFactory
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonComplianceStub.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonComplianceStub.golden
index 39dc2df47161..fc4fcbf22545 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonComplianceStub.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonComplianceStub.golden
@@ -26,6 +26,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -33,6 +34,7 @@ import javax.annotation.Generated;
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class HttpJsonComplianceStub extends ComplianceStub {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonEchoStub.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonEchoStub.golden
index 443511805263..3c02a78ccd8f 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonEchoStub.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonEchoStub.golden
@@ -45,6 +45,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -52,6 +53,7 @@ import javax.annotation.Generated;
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class HttpJsonEchoStub extends EchoStub {
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonResourceNameExtractorStub.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonResourceNameExtractorStub.golden
index ee8722706bd8..c4552d93999e 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonResourceNameExtractorStub.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonResourceNameExtractorStub.golden
@@ -34,6 +34,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -41,6 +42,7 @@ import javax.annotation.Generated;
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class HttpJsonResourceNameExtractorTestingStub extends ResourceNameExtractorTestingStub {
   private static final TypeRegistry typeRegistry = TypeRegistry.newBuilder().build();
diff --git a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonRoutingHeadersStub.golden b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonRoutingHeadersStub.golden
index b377fe3a181f..e75975005600 100644
--- a/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonRoutingHeadersStub.golden
+++ b/sdk-platform-java/gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/HttpJsonRoutingHeadersStub.golden
@@ -26,6 +26,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -33,6 +34,7 @@ import javax.annotation.Generated;
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class HttpJsonExplicitDynamicRoutingHeaderTestingStub
     extends ExplicitDynamicRoutingHeaderTestingStub {
diff --git a/sdk-platform-java/gax-java/dependencies.properties b/sdk-platform-java/gax-java/dependencies.properties
index 50cb9dc8de0b..1cf7a0cc71c9 100644
--- a/sdk-platform-java/gax-java/dependencies.properties
+++ b/sdk-platform-java/gax-java/dependencies.properties
@@ -81,6 +81,7 @@ maven.org_slf4j_slf4j_api=org.slf4j:slf4j-api:2.0.16
 maven.com_google_protobuf_protobuf_java_util=com.google.protobuf:protobuf-java-util:3.25.5
 
 # Testing maven artifacts
+maven.org_jspecify_jspecify=org.jspecify:jspecify:1.0.0
 maven.junit_junit=junit:junit:4.13.2
 maven.org_mockito_mockito_core=org.mockito:mockito-core:4.11.0
 maven.org_mockito_mockito_junit_jupiter=org.mockito:mockito-junit-jupiter:4.11.0
diff --git a/sdk-platform-java/hermetic_build/library_generation/owlbot/templates/poms/cloud_pom.xml.j2 b/sdk-platform-java/hermetic_build/library_generation/owlbot/templates/poms/cloud_pom.xml.j2
index d0ae8cd7c56b..8978d8437e52 100644
--- a/sdk-platform-java/hermetic_build/library_generation/owlbot/templates/poms/cloud_pom.xml.j2
+++ b/sdk-platform-java/hermetic_build/library_generation/owlbot/templates/poms/cloud_pom.xml.j2
@@ -43,6 +43,11 @@
       <groupId>com.google.api.grpc</groupId>
       <artifactId>proto-google-common-protos</artifactId>
     </dependency>
+    <dependency>
+      <groupId>org.jspecify</groupId>
+      <artifactId>jspecify</artifactId>
+      <version>${jspecify.version}</version>
+    </dependency>
 {% for module in proto_modules %}
     <dependency>
       <groupId>{{module.group_id}}</groupId>
diff --git a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/ConnectionServiceClient.java b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/ConnectionServiceClient.java
index e9e1cef5dd06..11a4a43a6524 100644
--- a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/ConnectionServiceClient.java
+++ b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/ConnectionServiceClient.java
@@ -31,6 +31,7 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -142,6 +143,7 @@
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class ConnectionServiceClient implements BackgroundResource {
   private final ConnectionServiceSettings settings;
diff --git a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/ConnectionServiceSettings.java b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/ConnectionServiceSettings.java
index 335e0f4be326..f2095fd712b0 100644
--- a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/ConnectionServiceSettings.java
+++ b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/ConnectionServiceSettings.java
@@ -35,6 +35,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -86,6 +87,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class ConnectionServiceSettings extends ClientSettings<ConnectionServiceSettings> {
 
diff --git a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/EndpointName.java b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/EndpointName.java
index 16bf12e1638c..9c8e5208230c 100644
--- a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/EndpointName.java
+++ b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/EndpointName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class EndpointName implements ResourceName {
   private static final PathTemplate PROJECT_ENDPOINT =
diff --git a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/TetherClient.java b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/TetherClient.java
index f3cd1b0dc68f..bd296833e614 100644
--- a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/TetherClient.java
+++ b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/TetherClient.java
@@ -23,6 +23,7 @@
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -118,6 +119,7 @@
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class TetherClient implements BackgroundResource {
   private final TetherSettings settings;
diff --git a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/TetherSettings.java b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/TetherSettings.java
index 5c941f005e58..fbbdbe0359ef 100644
--- a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/TetherSettings.java
+++ b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/TetherSettings.java
@@ -31,6 +31,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -81,6 +82,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class TetherSettings extends ClientSettings<TetherSettings> {
 
diff --git a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/ConnectionServiceStub.java b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/ConnectionServiceStub.java
index c1235c18367d..25478406d58e 100644
--- a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/ConnectionServiceStub.java
+++ b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/ConnectionServiceStub.java
@@ -23,6 +23,7 @@
 import com.google.cloud.apigeeconnect.v1.ListConnectionsRequest;
 import com.google.cloud.apigeeconnect.v1.ListConnectionsResponse;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -30,6 +31,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public abstract class ConnectionServiceStub implements BackgroundResource {
 
diff --git a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/ConnectionServiceStubSettings.java b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/ConnectionServiceStubSettings.java
index 184451d6db32..08f2534708ee 100644
--- a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/ConnectionServiceStubSettings.java
+++ b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/ConnectionServiceStubSettings.java
@@ -56,6 +56,7 @@
 import java.time.Duration;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -108,6 +109,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
 public class ConnectionServiceStubSettings extends StubSettings<ConnectionServiceStubSettings> {
diff --git a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/GrpcConnectionServiceCallableFactory.java b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/GrpcConnectionServiceCallableFactory.java
index 5bbbfc3b1aa1..f24668061e45 100644
--- a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/GrpcConnectionServiceCallableFactory.java
+++ b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/GrpcConnectionServiceCallableFactory.java
@@ -34,6 +34,7 @@
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -41,6 +42,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcConnectionServiceCallableFactory implements GrpcStubCallableFactory {
 
diff --git a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/GrpcConnectionServiceStub.java b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/GrpcConnectionServiceStub.java
index 6e453159f7bf..1a65052651b8 100644
--- a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/GrpcConnectionServiceStub.java
+++ b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/GrpcConnectionServiceStub.java
@@ -34,6 +34,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -41,6 +42,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcConnectionServiceStub extends ConnectionServiceStub {
   private static final MethodDescriptor<ListConnectionsRequest, ListConnectionsResponse>
diff --git a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/GrpcTetherCallableFactory.java b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/GrpcTetherCallableFactory.java
index e9720bc945fd..3d2b4b80d68d 100644
--- a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/GrpcTetherCallableFactory.java
+++ b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/GrpcTetherCallableFactory.java
@@ -34,6 +34,7 @@
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -41,6 +42,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcTetherCallableFactory implements GrpcStubCallableFactory {
 
diff --git a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/GrpcTetherStub.java b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/GrpcTetherStub.java
index 396579ae685a..686ac740c547 100644
--- a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/GrpcTetherStub.java
+++ b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/GrpcTetherStub.java
@@ -30,6 +30,7 @@
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -37,6 +38,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcTetherStub extends TetherStub {
   private static final MethodDescriptor<EgressResponse, EgressRequest> egressMethodDescriptor =
diff --git a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/HttpJsonConnectionServiceCallableFactory.java b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/HttpJsonConnectionServiceCallableFactory.java
index 06e53d47b717..5a40b3849119 100644
--- a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/HttpJsonConnectionServiceCallableFactory.java
+++ b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/HttpJsonConnectionServiceCallableFactory.java
@@ -32,6 +32,7 @@
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.longrunning.Operation;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -39,6 +40,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class HttpJsonConnectionServiceCallableFactory
     implements HttpJsonStubCallableFactory<Operation, OperationsStub> {
diff --git a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/HttpJsonConnectionServiceStub.java b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/HttpJsonConnectionServiceStub.java
index 3cf8a205a409..86c9e0f106f4 100644
--- a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/HttpJsonConnectionServiceStub.java
+++ b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/HttpJsonConnectionServiceStub.java
@@ -40,6 +40,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -47,6 +48,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class HttpJsonConnectionServiceStub extends ConnectionServiceStub {
   private static final TypeRegistry typeRegistry = TypeRegistry.newBuilder().build();
diff --git a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/TetherStub.java b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/TetherStub.java
index affda077bafa..424bc479e782 100644
--- a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/TetherStub.java
+++ b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/TetherStub.java
@@ -21,6 +21,7 @@
 import com.google.cloud.apigeeconnect.v1.EgressRequest;
 import com.google.cloud.apigeeconnect.v1.EgressResponse;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -28,6 +29,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public abstract class TetherStub implements BackgroundResource {
 
diff --git a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/TetherStubSettings.java b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/TetherStubSettings.java
index 227a68e91ff0..f0a16c22b218 100644
--- a/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/TetherStubSettings.java
+++ b/sdk-platform-java/test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/TetherStubSettings.java
@@ -42,6 +42,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -92,6 +93,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
 public class TetherStubSettings extends StubSettings<TetherStubSettings> {
diff --git a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/AssetServiceClient.java b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/AssetServiceClient.java
index a7841addfda4..9e2be2079cca 100644
--- a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/AssetServiceClient.java
+++ b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/AssetServiceClient.java
@@ -39,6 +39,7 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -482,6 +483,7 @@
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class AssetServiceClient implements BackgroundResource {
   private final AssetServiceSettings settings;
diff --git a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/AssetServiceSettings.java b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/AssetServiceSettings.java
index 2319d4ff413b..137014ae6c20 100644
--- a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/AssetServiceSettings.java
+++ b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/AssetServiceSettings.java
@@ -41,6 +41,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -116,6 +117,7 @@
  *     .build();
  * }</pre>
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class AssetServiceSettings extends ClientSettings<AssetServiceSettings> {
 
diff --git a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/FeedName.java b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/FeedName.java
index b66fee59337e..ed33edd129ec 100644
--- a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/FeedName.java
+++ b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/FeedName.java
@@ -26,8 +26,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class FeedName implements ResourceName {
   private static final PathTemplate PROJECT_FEED =
diff --git a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/FolderName.java b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/FolderName.java
index 41c31e946a0f..29369cb83590 100644
--- a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/FolderName.java
+++ b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/FolderName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class FolderName implements ResourceName {
   private static final PathTemplate FOLDER =
diff --git a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/OrganizationName.java b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/OrganizationName.java
index 7ceca6182ac2..0cadf25e6184 100644
--- a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/OrganizationName.java
+++ b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/OrganizationName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class OrganizationName implements ResourceName {
   private static final PathTemplate ORGANIZATION =
diff --git a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/ProjectName.java b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/ProjectName.java
index 7e9b79905a12..e659b684f3f6 100644
--- a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/ProjectName.java
+++ b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/ProjectName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class ProjectName implements ResourceName {
   private static final PathTemplate PROJECT =
diff --git a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/SavedQueryName.java b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/SavedQueryName.java
index d2c3bc76638c..e565aefb9835 100644
--- a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/SavedQueryName.java
+++ b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/SavedQueryName.java
@@ -26,8 +26,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class SavedQueryName implements ResourceName {
   private static final PathTemplate PROJECT_SAVED_QUERY =
diff --git a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/AssetServiceStub.java b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/AssetServiceStub.java
index 442d70659293..d38f4b4b7703 100644
--- a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/AssetServiceStub.java
+++ b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/AssetServiceStub.java
@@ -63,6 +63,7 @@
 import com.google.longrunning.stub.OperationsStub;
 import com.google.protobuf.Empty;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -70,6 +71,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public abstract class AssetServiceStub implements BackgroundResource {
 
diff --git a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/AssetServiceStubSettings.java b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/AssetServiceStubSettings.java
index dddb8294c78b..14ec11890d20 100644
--- a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/AssetServiceStubSettings.java
+++ b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/AssetServiceStubSettings.java
@@ -100,6 +100,7 @@
 import java.time.Duration;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -177,6 +178,7 @@
  *     .build();
  * }</pre>
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
 public class AssetServiceStubSettings extends StubSettings<AssetServiceStubSettings> {
diff --git a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/GrpcAssetServiceCallableFactory.java b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/GrpcAssetServiceCallableFactory.java
index 242acd7db303..e1e74ecfdf07 100644
--- a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/GrpcAssetServiceCallableFactory.java
+++ b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/GrpcAssetServiceCallableFactory.java
@@ -34,6 +34,7 @@
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -41,6 +42,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcAssetServiceCallableFactory implements GrpcStubCallableFactory {
 
diff --git a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/GrpcAssetServiceStub.java b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/GrpcAssetServiceStub.java
index cf4e9beb8951..57f5e3e4a599 100644
--- a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/GrpcAssetServiceStub.java
+++ b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/GrpcAssetServiceStub.java
@@ -73,6 +73,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -80,6 +81,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcAssetServiceStub extends AssetServiceStub {
   private static final MethodDescriptor<ExportAssetsRequest, Operation>
diff --git a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/HttpJsonAssetServiceCallableFactory.java b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/HttpJsonAssetServiceCallableFactory.java
index 3e0878845ae1..994dbf67c729 100644
--- a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/HttpJsonAssetServiceCallableFactory.java
+++ b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/HttpJsonAssetServiceCallableFactory.java
@@ -32,6 +32,7 @@
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.longrunning.Operation;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -39,6 +40,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class HttpJsonAssetServiceCallableFactory
     implements HttpJsonStubCallableFactory<Operation, OperationsStub> {
diff --git a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/HttpJsonAssetServiceStub.java b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/HttpJsonAssetServiceStub.java
index 9c6b1aa24e73..85623f708e6e 100644
--- a/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/HttpJsonAssetServiceStub.java
+++ b/sdk-platform-java/test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/HttpJsonAssetServiceStub.java
@@ -82,6 +82,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -89,6 +90,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class HttpJsonAssetServiceStub extends AssetServiceStub {
   private static final TypeRegistry typeRegistry =
diff --git a/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/bigtable/v2/InstanceName.java b/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/bigtable/v2/InstanceName.java
index d36d4f04c14a..6e36641b3114 100644
--- a/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/bigtable/v2/InstanceName.java
+++ b/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/bigtable/v2/InstanceName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class InstanceName implements ResourceName {
   private static final PathTemplate PROJECT_INSTANCE =
diff --git a/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/bigtable/v2/TableName.java b/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/bigtable/v2/TableName.java
index b616cb8488fc..200ca73023f9 100644
--- a/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/bigtable/v2/TableName.java
+++ b/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/bigtable/v2/TableName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class TableName implements ResourceName {
   private static final PathTemplate PROJECT_INSTANCE_TABLE =
diff --git a/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/BaseBigtableDataClient.java b/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/BaseBigtableDataClient.java
index 66354a487f61..f4b922e30f27 100644
--- a/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/BaseBigtableDataClient.java
+++ b/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/BaseBigtableDataClient.java
@@ -45,6 +45,7 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -235,6 +236,7 @@
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class BaseBigtableDataClient implements BackgroundResource {
   private final BaseBigtableDataSettings settings;
diff --git a/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/BaseBigtableDataSettings.java b/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/BaseBigtableDataSettings.java
index 9c85d1d69af1..728748a3dd7a 100644
--- a/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/BaseBigtableDataSettings.java
+++ b/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/BaseBigtableDataSettings.java
@@ -45,6 +45,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -96,6 +97,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class BaseBigtableDataSettings extends ClientSettings<BaseBigtableDataSettings> {
 
diff --git a/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/stub/BigtableStub.java b/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/stub/BigtableStub.java
index 3560cde528d3..e1e39ce76221 100644
--- a/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/stub/BigtableStub.java
+++ b/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/stub/BigtableStub.java
@@ -34,6 +34,7 @@
 import com.google.bigtable.v2.SampleRowKeysRequest;
 import com.google.bigtable.v2.SampleRowKeysResponse;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -41,6 +42,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public abstract class BigtableStub implements BackgroundResource {
 
diff --git a/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/stub/BigtableStubSettings.java b/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/stub/BigtableStubSettings.java
index 23374ac7802b..680112fc2920 100644
--- a/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/stub/BigtableStubSettings.java
+++ b/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/stub/BigtableStubSettings.java
@@ -55,6 +55,7 @@
 import java.time.Duration;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -106,6 +107,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
 public class BigtableStubSettings extends StubSettings<BigtableStubSettings> {
diff --git a/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/stub/GrpcBigtableCallableFactory.java b/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/stub/GrpcBigtableCallableFactory.java
index a7be4becd9ae..0ec0d12ba370 100644
--- a/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/stub/GrpcBigtableCallableFactory.java
+++ b/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/stub/GrpcBigtableCallableFactory.java
@@ -34,6 +34,7 @@
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -41,6 +42,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcBigtableCallableFactory implements GrpcStubCallableFactory {
 
diff --git a/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/stub/GrpcBigtableStub.java b/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/stub/GrpcBigtableStub.java
index 81a698650bde..333fd03ec358 100644
--- a/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/stub/GrpcBigtableStub.java
+++ b/sdk-platform-java/test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/stub/GrpcBigtableStub.java
@@ -46,6 +46,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -53,6 +54,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcBigtableStub extends BigtableStub {
   private static final MethodDescriptor<ReadRowsRequest, ReadRowsResponse>
diff --git a/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/AddressesClient.java b/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/AddressesClient.java
index 4807e593af20..7ae225f7cdfb 100644
--- a/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/AddressesClient.java
+++ b/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/AddressesClient.java
@@ -34,6 +34,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -186,6 +187,7 @@
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class AddressesClient implements BackgroundResource {
   private final AddressesSettings settings;
diff --git a/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/AddressesSettings.java b/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/AddressesSettings.java
index 9a69837dd37d..1d092e884e40 100644
--- a/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/AddressesSettings.java
+++ b/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/AddressesSettings.java
@@ -35,6 +35,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -110,6 +111,7 @@
  *     .build();
  * }</pre>
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class AddressesSettings extends ClientSettings<AddressesSettings> {
 
diff --git a/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/RegionOperationsClient.java b/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/RegionOperationsClient.java
index fa6c2a73ccea..8531bab2388b 100644
--- a/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/RegionOperationsClient.java
+++ b/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/RegionOperationsClient.java
@@ -23,6 +23,7 @@
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -136,6 +137,7 @@
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class RegionOperationsClient implements BackgroundResource {
   private final RegionOperationsSettings settings;
diff --git a/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/RegionOperationsSettings.java b/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/RegionOperationsSettings.java
index 670ba5b3d1b2..4104ee49c9f2 100644
--- a/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/RegionOperationsSettings.java
+++ b/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/RegionOperationsSettings.java
@@ -30,6 +30,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -81,6 +82,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class RegionOperationsSettings extends ClientSettings<RegionOperationsSettings> {
 
diff --git a/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/AddressesStub.java b/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/AddressesStub.java
index c0539366139a..ed3b92afde6d 100644
--- a/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/AddressesStub.java
+++ b/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/AddressesStub.java
@@ -30,6 +30,7 @@
 import com.google.cloud.compute.v1small.ListAddressesRequest;
 import com.google.cloud.compute.v1small.Operation;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -37,6 +38,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public abstract class AddressesStub implements BackgroundResource {
 
diff --git a/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/AddressesStubSettings.java b/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/AddressesStubSettings.java
index 3ae9929a1539..114d5a8d9b4a 100644
--- a/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/AddressesStubSettings.java
+++ b/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/AddressesStubSettings.java
@@ -64,6 +64,7 @@
 import java.util.List;
 import java.util.Map;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -139,6 +140,7 @@
  *     .build();
  * }</pre>
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
 public class AddressesStubSettings extends StubSettings<AddressesStubSettings> {
diff --git a/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/HttpJsonAddressesCallableFactory.java b/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/HttpJsonAddressesCallableFactory.java
index 82c30e674ae2..89a2d2ed8bac 100644
--- a/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/HttpJsonAddressesCallableFactory.java
+++ b/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/HttpJsonAddressesCallableFactory.java
@@ -31,6 +31,7 @@
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.cloud.compute.v1small.Operation;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -38,6 +39,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class HttpJsonAddressesCallableFactory
     implements HttpJsonStubCallableFactory<Operation, RegionOperationsStub> {
diff --git a/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/HttpJsonAddressesStub.java b/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/HttpJsonAddressesStub.java
index 545ecf7a36a2..bc9caeb208de 100644
--- a/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/HttpJsonAddressesStub.java
+++ b/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/HttpJsonAddressesStub.java
@@ -51,6 +51,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -58,6 +59,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class HttpJsonAddressesStub extends AddressesStub {
   private static final TypeRegistry typeRegistry =
diff --git a/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/HttpJsonRegionOperationsCallableFactory.java b/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/HttpJsonRegionOperationsCallableFactory.java
index fd5187b104ab..732b7b0f1bca 100644
--- a/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/HttpJsonRegionOperationsCallableFactory.java
+++ b/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/HttpJsonRegionOperationsCallableFactory.java
@@ -32,6 +32,7 @@
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.longrunning.Operation;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -39,6 +40,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class HttpJsonRegionOperationsCallableFactory
     implements HttpJsonStubCallableFactory<Operation, OperationsStub> {
diff --git a/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/HttpJsonRegionOperationsStub.java b/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/HttpJsonRegionOperationsStub.java
index d0ef4b45db7c..e87d888844c3 100644
--- a/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/HttpJsonRegionOperationsStub.java
+++ b/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/HttpJsonRegionOperationsStub.java
@@ -46,6 +46,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -53,6 +54,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class HttpJsonRegionOperationsStub extends RegionOperationsStub {
   private static final TypeRegistry typeRegistry = TypeRegistry.newBuilder().build();
diff --git a/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/RegionOperationsStub.java b/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/RegionOperationsStub.java
index 94ac7ea0a833..bda6f3bed672 100644
--- a/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/RegionOperationsStub.java
+++ b/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/RegionOperationsStub.java
@@ -23,6 +23,7 @@
 import com.google.cloud.compute.v1small.Operation;
 import com.google.cloud.compute.v1small.WaitRegionOperationRequest;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -30,6 +31,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public abstract class RegionOperationsStub implements BackgroundResource {
 
diff --git a/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/RegionOperationsStubSettings.java b/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/RegionOperationsStubSettings.java
index b2d447967627..1c66a2b510e2 100644
--- a/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/RegionOperationsStubSettings.java
+++ b/sdk-platform-java/test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/RegionOperationsStubSettings.java
@@ -43,6 +43,7 @@
 import java.time.Duration;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -94,6 +95,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
 public class RegionOperationsStubSettings extends StubSettings<RegionOperationsStubSettings> {
diff --git a/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/IamCredentialsClient.java b/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/IamCredentialsClient.java
index 9480ea267ada..809d9f7bc606 100644
--- a/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/IamCredentialsClient.java
+++ b/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/IamCredentialsClient.java
@@ -26,6 +26,7 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -198,6 +199,7 @@
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class IamCredentialsClient implements BackgroundResource {
   private final IamCredentialsSettings settings;
diff --git a/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/IamCredentialsSettings.java b/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/IamCredentialsSettings.java
index 6a91546f378a..6c6d18c2ef46 100644
--- a/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/IamCredentialsSettings.java
+++ b/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/IamCredentialsSettings.java
@@ -32,6 +32,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -84,6 +85,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class IamCredentialsSettings extends ClientSettings<IamCredentialsSettings> {
 
diff --git a/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/ServiceAccountName.java b/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/ServiceAccountName.java
index d538857c2abd..29071fff8871 100644
--- a/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/ServiceAccountName.java
+++ b/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/ServiceAccountName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class ServiceAccountName implements ResourceName {
   private static final PathTemplate PROJECT_SERVICE_ACCOUNT =
diff --git a/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/GrpcIamCredentialsCallableFactory.java b/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/GrpcIamCredentialsCallableFactory.java
index 719369a4a764..37097115994c 100644
--- a/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/GrpcIamCredentialsCallableFactory.java
+++ b/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/GrpcIamCredentialsCallableFactory.java
@@ -34,6 +34,7 @@
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -41,6 +42,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcIamCredentialsCallableFactory implements GrpcStubCallableFactory {
 
diff --git a/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/GrpcIamCredentialsStub.java b/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/GrpcIamCredentialsStub.java
index 7bcb37dd59b0..b54a7efe152d 100644
--- a/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/GrpcIamCredentialsStub.java
+++ b/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/GrpcIamCredentialsStub.java
@@ -38,6 +38,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -45,6 +46,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcIamCredentialsStub extends IamCredentialsStub {
   private static final MethodDescriptor<GenerateAccessTokenRequest, GenerateAccessTokenResponse>
diff --git a/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/HttpJsonIamCredentialsCallableFactory.java b/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/HttpJsonIamCredentialsCallableFactory.java
index fcd9f51b7a58..9de801ce60a8 100644
--- a/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/HttpJsonIamCredentialsCallableFactory.java
+++ b/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/HttpJsonIamCredentialsCallableFactory.java
@@ -32,6 +32,7 @@
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.longrunning.Operation;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -39,6 +40,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class HttpJsonIamCredentialsCallableFactory
     implements HttpJsonStubCallableFactory<Operation, OperationsStub> {
diff --git a/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/HttpJsonIamCredentialsStub.java b/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/HttpJsonIamCredentialsStub.java
index 979fd23d1103..5acc718825c6 100644
--- a/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/HttpJsonIamCredentialsStub.java
+++ b/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/HttpJsonIamCredentialsStub.java
@@ -44,6 +44,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -51,6 +52,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class HttpJsonIamCredentialsStub extends IamCredentialsStub {
   private static final TypeRegistry typeRegistry = TypeRegistry.newBuilder().build();
diff --git a/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/IamCredentialsStub.java b/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/IamCredentialsStub.java
index e7a22e224f0e..3558f1c6f5e0 100644
--- a/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/IamCredentialsStub.java
+++ b/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/IamCredentialsStub.java
@@ -27,6 +27,7 @@
 import com.google.cloud.iam.credentials.v1.SignJwtRequest;
 import com.google.cloud.iam.credentials.v1.SignJwtResponse;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -34,6 +35,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public abstract class IamCredentialsStub implements BackgroundResource {
 
diff --git a/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/IamCredentialsStubSettings.java b/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/IamCredentialsStubSettings.java
index 425b0e81fe7d..21c092c1e3a2 100644
--- a/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/IamCredentialsStubSettings.java
+++ b/sdk-platform-java/test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/IamCredentialsStubSettings.java
@@ -52,6 +52,7 @@
 import java.time.Duration;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -104,6 +105,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
 public class IamCredentialsStubSettings extends StubSettings<IamCredentialsStubSettings> {
diff --git a/sdk-platform-java/test/integration/goldens/iam/src/com/google/iam/v1/IAMPolicyClient.java b/sdk-platform-java/test/integration/goldens/iam/src/com/google/iam/v1/IAMPolicyClient.java
index 2e72baf90ed3..0599d925334f 100644
--- a/sdk-platform-java/test/integration/goldens/iam/src/com/google/iam/v1/IAMPolicyClient.java
+++ b/sdk-platform-java/test/integration/goldens/iam/src/com/google/iam/v1/IAMPolicyClient.java
@@ -23,6 +23,7 @@
 import java.io.IOException;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -164,6 +165,7 @@
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class IAMPolicyClient implements BackgroundResource {
   private final IAMPolicySettings settings;
diff --git a/sdk-platform-java/test/integration/goldens/iam/src/com/google/iam/v1/IAMPolicySettings.java b/sdk-platform-java/test/integration/goldens/iam/src/com/google/iam/v1/IAMPolicySettings.java
index 560c59690c11..3a3621b77e58 100644
--- a/sdk-platform-java/test/integration/goldens/iam/src/com/google/iam/v1/IAMPolicySettings.java
+++ b/sdk-platform-java/test/integration/goldens/iam/src/com/google/iam/v1/IAMPolicySettings.java
@@ -30,6 +30,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -80,6 +81,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class IAMPolicySettings extends ClientSettings<IAMPolicySettings> {
 
diff --git a/sdk-platform-java/test/integration/goldens/iam/src/com/google/iam/v1/stub/GrpcIAMPolicyCallableFactory.java b/sdk-platform-java/test/integration/goldens/iam/src/com/google/iam/v1/stub/GrpcIAMPolicyCallableFactory.java
index 3335d37bae7d..96547b3d7ca0 100644
--- a/sdk-platform-java/test/integration/goldens/iam/src/com/google/iam/v1/stub/GrpcIAMPolicyCallableFactory.java
+++ b/sdk-platform-java/test/integration/goldens/iam/src/com/google/iam/v1/stub/GrpcIAMPolicyCallableFactory.java
@@ -34,6 +34,7 @@
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -41,6 +42,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcIAMPolicyCallableFactory implements GrpcStubCallableFactory {
 
diff --git a/sdk-platform-java/test/integration/goldens/iam/src/com/google/iam/v1/stub/GrpcIAMPolicyStub.java b/sdk-platform-java/test/integration/goldens/iam/src/com/google/iam/v1/stub/GrpcIAMPolicyStub.java
index 4bee05992bba..11c267d3a7f2 100644
--- a/sdk-platform-java/test/integration/goldens/iam/src/com/google/iam/v1/stub/GrpcIAMPolicyStub.java
+++ b/sdk-platform-java/test/integration/goldens/iam/src/com/google/iam/v1/stub/GrpcIAMPolicyStub.java
@@ -35,6 +35,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -42,6 +43,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcIAMPolicyStub extends IAMPolicyStub {
   private static final MethodDescriptor<SetIamPolicyRequest, Policy> setIamPolicyMethodDescriptor =
diff --git a/sdk-platform-java/test/integration/goldens/iam/src/com/google/iam/v1/stub/IAMPolicyStub.java b/sdk-platform-java/test/integration/goldens/iam/src/com/google/iam/v1/stub/IAMPolicyStub.java
index 1c4324ca87c2..da78e573d479 100644
--- a/sdk-platform-java/test/integration/goldens/iam/src/com/google/iam/v1/stub/IAMPolicyStub.java
+++ b/sdk-platform-java/test/integration/goldens/iam/src/com/google/iam/v1/stub/IAMPolicyStub.java
@@ -24,6 +24,7 @@
 import com.google.iam.v1.TestIamPermissionsRequest;
 import com.google.iam.v1.TestIamPermissionsResponse;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -31,6 +32,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public abstract class IAMPolicyStub implements BackgroundResource {
 
diff --git a/sdk-platform-java/test/integration/goldens/iam/src/com/google/iam/v1/stub/IAMPolicyStubSettings.java b/sdk-platform-java/test/integration/goldens/iam/src/com/google/iam/v1/stub/IAMPolicyStubSettings.java
index 23681831f557..7761748c268a 100644
--- a/sdk-platform-java/test/integration/goldens/iam/src/com/google/iam/v1/stub/IAMPolicyStubSettings.java
+++ b/sdk-platform-java/test/integration/goldens/iam/src/com/google/iam/v1/stub/IAMPolicyStubSettings.java
@@ -45,6 +45,7 @@
 import java.time.Duration;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -95,6 +96,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
 public class IAMPolicyStubSettings extends StubSettings<IAMPolicyStubSettings> {
diff --git a/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/CryptoKeyName.java b/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/CryptoKeyName.java
index 37789fe0fe4a..9926a26800fa 100644
--- a/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/CryptoKeyName.java
+++ b/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/CryptoKeyName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class CryptoKeyName implements ResourceName {
   private static final PathTemplate PROJECT_LOCATION_KEY_RING_CRYPTO_KEY =
diff --git a/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/CryptoKeyVersionName.java b/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/CryptoKeyVersionName.java
index 94c1acf7d3b3..c874db01eba9 100644
--- a/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/CryptoKeyVersionName.java
+++ b/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/CryptoKeyVersionName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class CryptoKeyVersionName implements ResourceName {
   private static final PathTemplate PROJECT_LOCATION_KEY_RING_CRYPTO_KEY_CRYPTO_KEY_VERSION =
diff --git a/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/ImportJobName.java b/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/ImportJobName.java
index 38d3595e2e1f..11769b9fcaec 100644
--- a/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/ImportJobName.java
+++ b/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/ImportJobName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class ImportJobName implements ResourceName {
   private static final PathTemplate PROJECT_LOCATION_KEY_RING_IMPORT_JOB =
diff --git a/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/KeyManagementServiceClient.java b/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/KeyManagementServiceClient.java
index 6d24c630c70f..2346dcd09a38 100644
--- a/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/KeyManagementServiceClient.java
+++ b/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/KeyManagementServiceClient.java
@@ -42,6 +42,7 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -630,6 +631,7 @@
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class KeyManagementServiceClient implements BackgroundResource {
   private final KeyManagementServiceSettings settings;
diff --git a/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/KeyManagementServiceSettings.java b/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/KeyManagementServiceSettings.java
index e838a395e319..61f4951cdc4c 100644
--- a/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/KeyManagementServiceSettings.java
+++ b/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/KeyManagementServiceSettings.java
@@ -45,6 +45,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -97,6 +98,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class KeyManagementServiceSettings extends ClientSettings<KeyManagementServiceSettings> {
 
diff --git a/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/KeyRingName.java b/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/KeyRingName.java
index d2ec54cdcfbd..b2faeab39438 100644
--- a/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/KeyRingName.java
+++ b/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/KeyRingName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class KeyRingName implements ResourceName {
   private static final PathTemplate PROJECT_LOCATION_KEY_RING =
diff --git a/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/LocationName.java b/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/LocationName.java
index 7c0935ae37dc..8d115370779b 100644
--- a/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/LocationName.java
+++ b/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/LocationName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class LocationName implements ResourceName {
   private static final PathTemplate PROJECT_LOCATION =
diff --git a/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/stub/GrpcKeyManagementServiceCallableFactory.java b/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/stub/GrpcKeyManagementServiceCallableFactory.java
index fe3fa2622bb0..546f05449d9e 100644
--- a/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/stub/GrpcKeyManagementServiceCallableFactory.java
+++ b/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/stub/GrpcKeyManagementServiceCallableFactory.java
@@ -34,6 +34,7 @@
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -41,6 +42,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcKeyManagementServiceCallableFactory implements GrpcStubCallableFactory {
 
diff --git a/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/stub/GrpcKeyManagementServiceStub.java b/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/stub/GrpcKeyManagementServiceStub.java
index d88a498dd169..5c94dbfd3150 100644
--- a/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/stub/GrpcKeyManagementServiceStub.java
+++ b/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/stub/GrpcKeyManagementServiceStub.java
@@ -80,6 +80,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -87,6 +88,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcKeyManagementServiceStub extends KeyManagementServiceStub {
   private static final MethodDescriptor<ListKeyRingsRequest, ListKeyRingsResponse>
diff --git a/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/stub/KeyManagementServiceStub.java b/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/stub/KeyManagementServiceStub.java
index b23cdac8545e..a7c184645481 100644
--- a/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/stub/KeyManagementServiceStub.java
+++ b/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/stub/KeyManagementServiceStub.java
@@ -69,6 +69,7 @@
 import com.google.iam.v1.TestIamPermissionsRequest;
 import com.google.iam.v1.TestIamPermissionsResponse;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -76,6 +77,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public abstract class KeyManagementServiceStub implements BackgroundResource {
 
diff --git a/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/stub/KeyManagementServiceStubSettings.java b/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/stub/KeyManagementServiceStubSettings.java
index 614f4a5b7543..b2398a668d42 100644
--- a/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/stub/KeyManagementServiceStubSettings.java
+++ b/sdk-platform-java/test/integration/goldens/kms/src/com/google/cloud/kms/v1/stub/KeyManagementServiceStubSettings.java
@@ -97,6 +97,7 @@
 import java.time.Duration;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -149,6 +150,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
 public class KeyManagementServiceStubSettings
diff --git a/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/LibraryServiceClient.java b/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/LibraryServiceClient.java
index 9dcad1502321..7146943da73b 100644
--- a/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/LibraryServiceClient.java
+++ b/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/LibraryServiceClient.java
@@ -50,6 +50,7 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -351,6 +352,7 @@
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class LibraryServiceClient implements BackgroundResource {
   private final LibraryServiceSettings settings;
diff --git a/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/LibraryServiceSettings.java b/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/LibraryServiceSettings.java
index 20bd7f01c526..2bd7ba039c9c 100644
--- a/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/LibraryServiceSettings.java
+++ b/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/LibraryServiceSettings.java
@@ -52,6 +52,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -104,6 +105,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class LibraryServiceSettings extends ClientSettings<LibraryServiceSettings> {
 
diff --git a/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/GrpcLibraryServiceCallableFactory.java b/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/GrpcLibraryServiceCallableFactory.java
index 5c3abfedf03d..18005b22c8b9 100644
--- a/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/GrpcLibraryServiceCallableFactory.java
+++ b/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/GrpcLibraryServiceCallableFactory.java
@@ -34,6 +34,7 @@
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -41,6 +42,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcLibraryServiceCallableFactory implements GrpcStubCallableFactory {
 
diff --git a/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/GrpcLibraryServiceStub.java b/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/GrpcLibraryServiceStub.java
index fdf52125892b..ee7832edc449 100644
--- a/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/GrpcLibraryServiceStub.java
+++ b/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/GrpcLibraryServiceStub.java
@@ -49,6 +49,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -56,6 +57,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcLibraryServiceStub extends LibraryServiceStub {
   private static final MethodDescriptor<CreateShelfRequest, Shelf> createShelfMethodDescriptor =
diff --git a/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/HttpJsonLibraryServiceCallableFactory.java b/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/HttpJsonLibraryServiceCallableFactory.java
index 9607f81ea19b..58598331549e 100644
--- a/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/HttpJsonLibraryServiceCallableFactory.java
+++ b/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/HttpJsonLibraryServiceCallableFactory.java
@@ -32,6 +32,7 @@
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.longrunning.Operation;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -39,6 +40,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class HttpJsonLibraryServiceCallableFactory
     implements HttpJsonStubCallableFactory<Operation, OperationsStub> {
diff --git a/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/HttpJsonLibraryServiceStub.java b/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/HttpJsonLibraryServiceStub.java
index ff6f3983860e..1169d4f4afcb 100644
--- a/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/HttpJsonLibraryServiceStub.java
+++ b/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/HttpJsonLibraryServiceStub.java
@@ -55,6 +55,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -62,6 +63,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class HttpJsonLibraryServiceStub extends LibraryServiceStub {
   private static final TypeRegistry typeRegistry = TypeRegistry.newBuilder().build();
diff --git a/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/LibraryServiceStub.java b/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/LibraryServiceStub.java
index e1a94b7f25c5..e9509bdef3e4 100644
--- a/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/LibraryServiceStub.java
+++ b/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/LibraryServiceStub.java
@@ -38,6 +38,7 @@
 import com.google.example.library.v1.UpdateBookRequest;
 import com.google.protobuf.Empty;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -45,6 +46,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public abstract class LibraryServiceStub implements BackgroundResource {
 
diff --git a/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/LibraryServiceStubSettings.java b/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/LibraryServiceStubSettings.java
index f4774ebdb5eb..8e74f9c6e25d 100644
--- a/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/LibraryServiceStubSettings.java
+++ b/sdk-platform-java/test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/LibraryServiceStubSettings.java
@@ -70,6 +70,7 @@
 import java.time.Duration;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -122,6 +123,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
 public class LibraryServiceStubSettings extends StubSettings<LibraryServiceStubSettings> {
diff --git a/sdk-platform-java/test/integration/goldens/library/src/com/google/example/library/v1/BookName.java b/sdk-platform-java/test/integration/goldens/library/src/com/google/example/library/v1/BookName.java
index 917a994babda..a115d587e51d 100644
--- a/sdk-platform-java/test/integration/goldens/library/src/com/google/example/library/v1/BookName.java
+++ b/sdk-platform-java/test/integration/goldens/library/src/com/google/example/library/v1/BookName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class BookName implements ResourceName {
   private static final PathTemplate SHELF_BOOK =
diff --git a/sdk-platform-java/test/integration/goldens/library/src/com/google/example/library/v1/ShelfName.java b/sdk-platform-java/test/integration/goldens/library/src/com/google/example/library/v1/ShelfName.java
index 41e22d15da94..172ce6f1d71c 100644
--- a/sdk-platform-java/test/integration/goldens/library/src/com/google/example/library/v1/ShelfName.java
+++ b/sdk-platform-java/test/integration/goldens/library/src/com/google/example/library/v1/ShelfName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class ShelfName implements ResourceName {
   private static final PathTemplate SHELF_ID =
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/ConfigClient.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/ConfigClient.java
index 3ac4f9af1202..3b949565cc9e 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/ConfigClient.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/ConfigClient.java
@@ -86,6 +86,7 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -630,6 +631,7 @@
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class ConfigClient implements BackgroundResource {
   private final ConfigSettings settings;
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/ConfigSettings.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/ConfigSettings.java
index 7dbd629d5fe8..2904dc6ec896 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/ConfigSettings.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/ConfigSettings.java
@@ -77,6 +77,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -152,6 +153,7 @@
  *     .build();
  * }</pre>
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class ConfigSettings extends ClientSettings<ConfigSettings> {
 
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/LoggingClient.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/LoggingClient.java
index 9390d279af30..707c661a9e79 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/LoggingClient.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/LoggingClient.java
@@ -53,6 +53,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -228,6 +229,7 @@
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class LoggingClient implements BackgroundResource {
   private final LoggingSettings settings;
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/LoggingSettings.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/LoggingSettings.java
index 1a740d51f0f7..47c2092a47ac 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/LoggingSettings.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/LoggingSettings.java
@@ -49,6 +49,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -99,6 +100,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class LoggingSettings extends ClientSettings<LoggingSettings> {
 
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/MetricsClient.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/MetricsClient.java
index 8ee3f62074e8..298de5923a4d 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/MetricsClient.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/MetricsClient.java
@@ -41,6 +41,7 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -207,6 +208,7 @@
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class MetricsClient implements BackgroundResource {
   private final MetricsSettings settings;
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/MetricsSettings.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/MetricsSettings.java
index 2176a3c1e1d2..5c6c60c6028e 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/MetricsSettings.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/MetricsSettings.java
@@ -41,6 +41,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -91,6 +92,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class MetricsSettings extends ClientSettings<MetricsSettings> {
 
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/ConfigServiceV2Stub.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/ConfigServiceV2Stub.java
index 87d63ca97dde..23c72df8c13f 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/ConfigServiceV2Stub.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/ConfigServiceV2Stub.java
@@ -66,6 +66,7 @@
 import com.google.longrunning.stub.OperationsStub;
 import com.google.protobuf.Empty;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -73,6 +74,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public abstract class ConfigServiceV2Stub implements BackgroundResource {
 
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/ConfigServiceV2StubSettings.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/ConfigServiceV2StubSettings.java
index 76d8a313162b..a9fb32db8506 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/ConfigServiceV2StubSettings.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/ConfigServiceV2StubSettings.java
@@ -96,6 +96,7 @@
 import java.time.Duration;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -173,6 +174,7 @@
  *     .build();
  * }</pre>
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
 public class ConfigServiceV2StubSettings extends StubSettings<ConfigServiceV2StubSettings> {
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/GrpcConfigServiceV2CallableFactory.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/GrpcConfigServiceV2CallableFactory.java
index e37c3746ba55..7848f2f91655 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/GrpcConfigServiceV2CallableFactory.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/GrpcConfigServiceV2CallableFactory.java
@@ -34,6 +34,7 @@
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -41,6 +42,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcConfigServiceV2CallableFactory implements GrpcStubCallableFactory {
 
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/GrpcConfigServiceV2Stub.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/GrpcConfigServiceV2Stub.java
index 424b550eec5c..2853af9453a4 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/GrpcConfigServiceV2Stub.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/GrpcConfigServiceV2Stub.java
@@ -76,6 +76,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -83,6 +84,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcConfigServiceV2Stub extends ConfigServiceV2Stub {
   private static final MethodDescriptor<ListBucketsRequest, ListBucketsResponse>
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/GrpcLoggingServiceV2CallableFactory.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/GrpcLoggingServiceV2CallableFactory.java
index 2ea721e819a5..0e603e59e1f7 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/GrpcLoggingServiceV2CallableFactory.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/GrpcLoggingServiceV2CallableFactory.java
@@ -34,6 +34,7 @@
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -41,6 +42,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcLoggingServiceV2CallableFactory implements GrpcStubCallableFactory {
 
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/GrpcLoggingServiceV2Stub.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/GrpcLoggingServiceV2Stub.java
index 45064851889e..1021cdbeb468 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/GrpcLoggingServiceV2Stub.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/GrpcLoggingServiceV2Stub.java
@@ -47,6 +47,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -54,6 +55,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcLoggingServiceV2Stub extends LoggingServiceV2Stub {
   private static final MethodDescriptor<DeleteLogRequest, Empty> deleteLogMethodDescriptor =
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/GrpcMetricsServiceV2CallableFactory.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/GrpcMetricsServiceV2CallableFactory.java
index d64bb1b3fb61..b86840e0dd06 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/GrpcMetricsServiceV2CallableFactory.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/GrpcMetricsServiceV2CallableFactory.java
@@ -34,6 +34,7 @@
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -41,6 +42,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcMetricsServiceV2CallableFactory implements GrpcStubCallableFactory {
 
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/GrpcMetricsServiceV2Stub.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/GrpcMetricsServiceV2Stub.java
index 5d8e5dfcd366..9531166314ba 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/GrpcMetricsServiceV2Stub.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/GrpcMetricsServiceV2Stub.java
@@ -40,6 +40,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -47,6 +48,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcMetricsServiceV2Stub extends MetricsServiceV2Stub {
   private static final MethodDescriptor<ListLogMetricsRequest, ListLogMetricsResponse>
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/LoggingServiceV2Stub.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/LoggingServiceV2Stub.java
index 5e2830d0e3e0..09084951ee4c 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/LoggingServiceV2Stub.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/LoggingServiceV2Stub.java
@@ -36,6 +36,7 @@
 import com.google.logging.v2.WriteLogEntriesResponse;
 import com.google.protobuf.Empty;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -43,6 +44,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public abstract class LoggingServiceV2Stub implements BackgroundResource {
 
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/LoggingServiceV2StubSettings.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/LoggingServiceV2StubSettings.java
index 38a71668b15e..129d2dce53ce 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/LoggingServiceV2StubSettings.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/LoggingServiceV2StubSettings.java
@@ -75,6 +75,7 @@
 import java.util.Collection;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -126,6 +127,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
 public class LoggingServiceV2StubSettings extends StubSettings<LoggingServiceV2StubSettings> {
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/MetricsServiceV2Stub.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/MetricsServiceV2Stub.java
index f546d2c26860..afbfe7d34893 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/MetricsServiceV2Stub.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/MetricsServiceV2Stub.java
@@ -29,6 +29,7 @@
 import com.google.logging.v2.UpdateLogMetricRequest;
 import com.google.protobuf.Empty;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -36,6 +37,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public abstract class MetricsServiceV2Stub implements BackgroundResource {
 
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/MetricsServiceV2StubSettings.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/MetricsServiceV2StubSettings.java
index 12ab94379c47..12c4baf63676 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/MetricsServiceV2StubSettings.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/cloud/logging/v2/stub/MetricsServiceV2StubSettings.java
@@ -57,6 +57,7 @@
 import java.time.Duration;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -108,6 +109,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
 public class MetricsServiceV2StubSettings extends StubSettings<MetricsServiceV2StubSettings> {
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/BillingAccountLocationName.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/BillingAccountLocationName.java
index 1a5aa5c8de05..178a8e99bf96 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/BillingAccountLocationName.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/BillingAccountLocationName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class BillingAccountLocationName implements ResourceName {
   private static final PathTemplate BILLING_ACCOUNT_LOCATION =
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/BillingAccountName.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/BillingAccountName.java
index 681a8031f749..7a0fcf839421 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/BillingAccountName.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/BillingAccountName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class BillingAccountName implements ResourceName {
   private static final PathTemplate BILLING_ACCOUNT =
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/CmekSettingsName.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/CmekSettingsName.java
index 07c7a115ab63..103c3a818915 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/CmekSettingsName.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/CmekSettingsName.java
@@ -26,8 +26,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class CmekSettingsName implements ResourceName {
   private static final PathTemplate PROJECT =
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/FolderLocationName.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/FolderLocationName.java
index 4860a1eb4424..4676ef17d701 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/FolderLocationName.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/FolderLocationName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class FolderLocationName implements ResourceName {
   private static final PathTemplate FOLDER_LOCATION =
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/FolderName.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/FolderName.java
index 2cb041189a60..ad975e6564ff 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/FolderName.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/FolderName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class FolderName implements ResourceName {
   private static final PathTemplate FOLDER =
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LocationName.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LocationName.java
index 6f29f3fd7e21..e869cb57f633 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LocationName.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LocationName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class LocationName implements ResourceName {
   private static final PathTemplate PROJECT_LOCATION =
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LogBucketName.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LogBucketName.java
index 03ecbe72fa5c..d5af1c62075b 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LogBucketName.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LogBucketName.java
@@ -26,8 +26,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class LogBucketName implements ResourceName {
   private static final PathTemplate PROJECT_LOCATION_BUCKET =
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LogExclusionName.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LogExclusionName.java
index 621994445785..f5deda544cd4 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LogExclusionName.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LogExclusionName.java
@@ -26,8 +26,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class LogExclusionName implements ResourceName {
   private static final PathTemplate PROJECT_EXCLUSION =
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LogMetricName.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LogMetricName.java
index 019696eea596..4ed25f0ecaf5 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LogMetricName.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LogMetricName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class LogMetricName implements ResourceName {
   private static final PathTemplate PROJECT_METRIC =
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LogName.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LogName.java
index b6bc4835f353..3e7c291fb43c 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LogName.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LogName.java
@@ -26,8 +26,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class LogName implements ResourceName {
   private static final PathTemplate PROJECT_LOG =
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LogSinkName.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LogSinkName.java
index 3e225abde9fc..9f8f86acccb5 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LogSinkName.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LogSinkName.java
@@ -26,8 +26,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class LogSinkName implements ResourceName {
   private static final PathTemplate PROJECT_SINK =
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LogViewName.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LogViewName.java
index 7a8e274b185c..83f47d206990 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LogViewName.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/LogViewName.java
@@ -26,8 +26,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class LogViewName implements ResourceName {
   private static final PathTemplate PROJECT_LOCATION_BUCKET_VIEW =
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/OrganizationLocationName.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/OrganizationLocationName.java
index a747d117eceb..63390df42c17 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/OrganizationLocationName.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/OrganizationLocationName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class OrganizationLocationName implements ResourceName {
   private static final PathTemplate ORGANIZATION_LOCATION =
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/OrganizationName.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/OrganizationName.java
index 44d1cb28d139..d90f4ff73657 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/OrganizationName.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/OrganizationName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class OrganizationName implements ResourceName {
   private static final PathTemplate ORGANIZATION =
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/ProjectName.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/ProjectName.java
index aa708f472427..2cc797351ff5 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/ProjectName.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/ProjectName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class ProjectName implements ResourceName {
   private static final PathTemplate PROJECT =
diff --git a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/SettingsName.java b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/SettingsName.java
index fbfdd7c0d1c8..4c3f9c69f7a6 100644
--- a/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/SettingsName.java
+++ b/sdk-platform-java/test/integration/goldens/logging/src/com/google/logging/v2/SettingsName.java
@@ -26,8 +26,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class SettingsName implements ResourceName {
   private static final PathTemplate PROJECT =
diff --git a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/SchemaServiceClient.java b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/SchemaServiceClient.java
index 859ae29a5f62..9ed9579c9353 100644
--- a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/SchemaServiceClient.java
+++ b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/SchemaServiceClient.java
@@ -54,6 +54,7 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -358,6 +359,7 @@
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class SchemaServiceClient implements BackgroundResource {
   private final SchemaServiceSettings settings;
diff --git a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/SchemaServiceSettings.java b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/SchemaServiceSettings.java
index bc1793ed7516..3a1bb72aaf88 100644
--- a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/SchemaServiceSettings.java
+++ b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/SchemaServiceSettings.java
@@ -55,6 +55,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -105,6 +106,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class SchemaServiceSettings extends ClientSettings<SchemaServiceSettings> {
 
diff --git a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/SubscriptionAdminClient.java b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/SubscriptionAdminClient.java
index 010cc884d23f..504c1ef5067e 100644
--- a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/SubscriptionAdminClient.java
+++ b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/SubscriptionAdminClient.java
@@ -65,6 +65,7 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -480,6 +481,7 @@
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class SubscriptionAdminClient implements BackgroundResource {
   private final SubscriptionAdminSettings settings;
diff --git a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/SubscriptionAdminSettings.java b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/SubscriptionAdminSettings.java
index 4afdf2718a0c..b5dea6fd00af 100644
--- a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/SubscriptionAdminSettings.java
+++ b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/SubscriptionAdminSettings.java
@@ -63,6 +63,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -114,6 +115,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class SubscriptionAdminSettings extends ClientSettings<SubscriptionAdminSettings> {
 
diff --git a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/TopicAdminClient.java b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/TopicAdminClient.java
index a02ba18b89b1..4017bf13db75 100644
--- a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/TopicAdminClient.java
+++ b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/TopicAdminClient.java
@@ -54,6 +54,7 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -334,6 +335,7 @@
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class TopicAdminClient implements BackgroundResource {
   private final TopicAdminSettings settings;
diff --git a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/TopicAdminSettings.java b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/TopicAdminSettings.java
index e089bdd5688c..3cd5c31abad1 100644
--- a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/TopicAdminSettings.java
+++ b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/TopicAdminSettings.java
@@ -56,6 +56,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -106,6 +107,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class TopicAdminSettings extends ClientSettings<TopicAdminSettings> {
 
diff --git a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/GrpcPublisherCallableFactory.java b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/GrpcPublisherCallableFactory.java
index 92adc0c86116..c7804ce55579 100644
--- a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/GrpcPublisherCallableFactory.java
+++ b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/GrpcPublisherCallableFactory.java
@@ -34,6 +34,7 @@
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -41,6 +42,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcPublisherCallableFactory implements GrpcStubCallableFactory {
 
diff --git a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/GrpcPublisherStub.java b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/GrpcPublisherStub.java
index 71c31ff8593e..28da8084068e 100644
--- a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/GrpcPublisherStub.java
+++ b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/GrpcPublisherStub.java
@@ -54,6 +54,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -61,6 +62,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcPublisherStub extends PublisherStub {
   private static final MethodDescriptor<Topic, Topic> createTopicMethodDescriptor =
diff --git a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/GrpcSchemaServiceCallableFactory.java b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/GrpcSchemaServiceCallableFactory.java
index 16236bc4bd0d..4f6d2494195e 100644
--- a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/GrpcSchemaServiceCallableFactory.java
+++ b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/GrpcSchemaServiceCallableFactory.java
@@ -34,6 +34,7 @@
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -41,6 +42,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcSchemaServiceCallableFactory implements GrpcStubCallableFactory {
 
diff --git a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/GrpcSchemaServiceStub.java b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/GrpcSchemaServiceStub.java
index 775b0ad332c0..6c3dcf58d2f7 100644
--- a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/GrpcSchemaServiceStub.java
+++ b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/GrpcSchemaServiceStub.java
@@ -54,6 +54,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -61,6 +62,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcSchemaServiceStub extends SchemaServiceStub {
   private static final MethodDescriptor<CreateSchemaRequest, Schema> createSchemaMethodDescriptor =
diff --git a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/GrpcSubscriberCallableFactory.java b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/GrpcSubscriberCallableFactory.java
index 8249a721942b..92193648b691 100644
--- a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/GrpcSubscriberCallableFactory.java
+++ b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/GrpcSubscriberCallableFactory.java
@@ -34,6 +34,7 @@
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -41,6 +42,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcSubscriberCallableFactory implements GrpcStubCallableFactory {
 
diff --git a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/GrpcSubscriberStub.java b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/GrpcSubscriberStub.java
index 02f4b0cce0e4..375d6bdb1ff7 100644
--- a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/GrpcSubscriberStub.java
+++ b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/GrpcSubscriberStub.java
@@ -62,6 +62,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -69,6 +70,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcSubscriberStub extends SubscriberStub {
   private static final MethodDescriptor<Subscription, Subscription>
diff --git a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/PublisherStub.java b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/PublisherStub.java
index 5c7f9d6a89be..8b1ab98e2311 100644
--- a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/PublisherStub.java
+++ b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/PublisherStub.java
@@ -43,6 +43,7 @@
 import com.google.pubsub.v1.Topic;
 import com.google.pubsub.v1.UpdateTopicRequest;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -50,6 +51,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public abstract class PublisherStub implements BackgroundResource {
 
diff --git a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/PublisherStubSettings.java b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/PublisherStubSettings.java
index 067d40923a32..30709fd96c19 100644
--- a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/PublisherStubSettings.java
+++ b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/PublisherStubSettings.java
@@ -81,6 +81,7 @@
 import java.util.Collection;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -131,6 +132,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
 public class PublisherStubSettings extends StubSettings<PublisherStubSettings> {
diff --git a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/SchemaServiceStub.java b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/SchemaServiceStub.java
index a0335a4b1fed..a06076e66b54 100644
--- a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/SchemaServiceStub.java
+++ b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/SchemaServiceStub.java
@@ -43,6 +43,7 @@
 import com.google.pubsub.v1.ValidateSchemaRequest;
 import com.google.pubsub.v1.ValidateSchemaResponse;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -50,6 +51,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public abstract class SchemaServiceStub implements BackgroundResource {
 
diff --git a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/SchemaServiceStubSettings.java b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/SchemaServiceStubSettings.java
index 6feb16de0c20..4871f04a3607 100644
--- a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/SchemaServiceStubSettings.java
+++ b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/SchemaServiceStubSettings.java
@@ -70,6 +70,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -121,6 +122,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
 public class SchemaServiceStubSettings extends StubSettings<SchemaServiceStubSettings> {
diff --git a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/SubscriberStub.java b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/SubscriberStub.java
index 115a2f2c82ae..13424d099837 100644
--- a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/SubscriberStub.java
+++ b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/SubscriberStub.java
@@ -51,6 +51,7 @@
 import com.google.pubsub.v1.UpdateSnapshotRequest;
 import com.google.pubsub.v1.UpdateSubscriptionRequest;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -58,6 +59,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public abstract class SubscriberStub implements BackgroundResource {
 
diff --git a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/SubscriberStubSettings.java b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/SubscriberStubSettings.java
index 4e1bcbc2596f..394af9a144ff 100644
--- a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/SubscriberStubSettings.java
+++ b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/cloud/pubsub/v1/stub/SubscriberStubSettings.java
@@ -79,6 +79,7 @@
 import java.time.Duration;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -130,6 +131,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
 public class SubscriberStubSettings extends StubSettings<SubscriberStubSettings> {
diff --git a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/pubsub/v1/ProjectName.java b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/pubsub/v1/ProjectName.java
index a4f599b17206..2db74834b0de 100644
--- a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/pubsub/v1/ProjectName.java
+++ b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/pubsub/v1/ProjectName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class ProjectName implements ResourceName {
   private static final PathTemplate PROJECT =
diff --git a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/pubsub/v1/SchemaName.java b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/pubsub/v1/SchemaName.java
index b3eaa772f014..a7fcd22be396 100644
--- a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/pubsub/v1/SchemaName.java
+++ b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/pubsub/v1/SchemaName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class SchemaName implements ResourceName {
   private static final PathTemplate PROJECT_SCHEMA =
diff --git a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/pubsub/v1/SnapshotName.java b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/pubsub/v1/SnapshotName.java
index a3a2342396c2..bbeafc6c4ddb 100644
--- a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/pubsub/v1/SnapshotName.java
+++ b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/pubsub/v1/SnapshotName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class SnapshotName implements ResourceName {
   private static final PathTemplate PROJECT_SNAPSHOT =
diff --git a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/pubsub/v1/SubscriptionName.java b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/pubsub/v1/SubscriptionName.java
index 2c12a10dcde1..8ea245778aab 100644
--- a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/pubsub/v1/SubscriptionName.java
+++ b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/pubsub/v1/SubscriptionName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class SubscriptionName implements ResourceName {
   private static final PathTemplate PROJECT_SUBSCRIPTION =
diff --git a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/pubsub/v1/TopicName.java b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/pubsub/v1/TopicName.java
index 798c74c892b7..5aa9b579ffbc 100644
--- a/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/pubsub/v1/TopicName.java
+++ b/sdk-platform-java/test/integration/goldens/pubsub/src/com/google/pubsub/v1/TopicName.java
@@ -26,8 +26,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class TopicName implements ResourceName {
   private static final PathTemplate PROJECT_TOPIC =
diff --git a/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/CloudRedisClient.java b/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/CloudRedisClient.java
index 61a4d254232d..abbea298e8e9 100644
--- a/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/CloudRedisClient.java
+++ b/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/CloudRedisClient.java
@@ -40,6 +40,7 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -371,6 +372,7 @@
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class CloudRedisClient implements BackgroundResource {
diff --git a/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/CloudRedisSettings.java b/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/CloudRedisSettings.java
index 94d6f4580a16..da404eee4abc 100644
--- a/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/CloudRedisSettings.java
+++ b/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/CloudRedisSettings.java
@@ -39,6 +39,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -114,6 +115,7 @@
  *     .build();
  * }</pre>
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class CloudRedisSettings extends ClientSettings<CloudRedisSettings> {
diff --git a/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/InstanceName.java b/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/InstanceName.java
index 58994ef5819b..603b9f8ca7ef 100644
--- a/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/InstanceName.java
+++ b/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/InstanceName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class InstanceName implements ResourceName {
   private static final PathTemplate PROJECT_LOCATION_INSTANCE =
diff --git a/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/LocationName.java b/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/LocationName.java
index 8ea7eca806dc..6b5c2f14a01f 100644
--- a/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/LocationName.java
+++ b/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/LocationName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class LocationName implements ResourceName {
   private static final PathTemplate PROJECT_LOCATION =
diff --git a/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/stub/CloudRedisStub.java b/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/stub/CloudRedisStub.java
index ee3b618be4b9..e68811a95d94 100644
--- a/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/stub/CloudRedisStub.java
+++ b/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/stub/CloudRedisStub.java
@@ -41,6 +41,7 @@
 import com.google.protobuf.Any;
 import com.google.protobuf.Empty;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -48,6 +49,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public abstract class CloudRedisStub implements BackgroundResource {
diff --git a/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/stub/CloudRedisStubSettings.java b/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/stub/CloudRedisStubSettings.java
index 6551856c0f32..c196c6066f9a 100644
--- a/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/stub/CloudRedisStubSettings.java
+++ b/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/stub/CloudRedisStubSettings.java
@@ -74,6 +74,7 @@
 import java.time.Duration;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -149,6 +150,7 @@
  *     .build();
  * }</pre>
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
diff --git a/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/stub/GrpcCloudRedisCallableFactory.java b/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/stub/GrpcCloudRedisCallableFactory.java
index 73f0d9dc6d65..c2d3ef3c3361 100644
--- a/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/stub/GrpcCloudRedisCallableFactory.java
+++ b/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/stub/GrpcCloudRedisCallableFactory.java
@@ -35,6 +35,7 @@
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -42,6 +43,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class GrpcCloudRedisCallableFactory implements GrpcStubCallableFactory {
diff --git a/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/stub/GrpcCloudRedisStub.java b/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/stub/GrpcCloudRedisStub.java
index 3668310283e2..817ff56f330c 100644
--- a/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/stub/GrpcCloudRedisStub.java
+++ b/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/stub/GrpcCloudRedisStub.java
@@ -51,6 +51,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -58,6 +59,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class GrpcCloudRedisStub extends CloudRedisStub {
diff --git a/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/stub/HttpJsonCloudRedisCallableFactory.java b/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/stub/HttpJsonCloudRedisCallableFactory.java
index dd0148220481..9b5d2e3c10bd 100644
--- a/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/stub/HttpJsonCloudRedisCallableFactory.java
+++ b/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/stub/HttpJsonCloudRedisCallableFactory.java
@@ -33,6 +33,7 @@
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.longrunning.Operation;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -40,6 +41,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class HttpJsonCloudRedisCallableFactory
diff --git a/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/stub/HttpJsonCloudRedisStub.java b/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/stub/HttpJsonCloudRedisStub.java
index 8e4ed2536565..19ffec240831 100644
--- a/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/stub/HttpJsonCloudRedisStub.java
+++ b/sdk-platform-java/test/integration/goldens/redis/src/com/google/cloud/redis/v1beta1/stub/HttpJsonCloudRedisStub.java
@@ -62,6 +62,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -69,6 +70,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @BetaApi
 @Generated("by gapic-generator-java")
 public class HttpJsonCloudRedisStub extends CloudRedisStub {
diff --git a/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/BucketName.java b/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/BucketName.java
index 67619b665fdb..64f36d73175a 100644
--- a/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/BucketName.java
+++ b/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/BucketName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class BucketName implements ResourceName {
   private static final PathTemplate PROJECT_BUCKET =
diff --git a/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/CryptoKeyName.java b/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/CryptoKeyName.java
index f10da50fb9e8..b9ccbab4b6fa 100644
--- a/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/CryptoKeyName.java
+++ b/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/CryptoKeyName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class CryptoKeyName implements ResourceName {
   private static final PathTemplate PROJECT_LOCATION_KEY_RING_CRYPTO_KEY =
diff --git a/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/NotificationName.java b/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/NotificationName.java
index f69d2add31ac..5e33a2ad301e 100644
--- a/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/NotificationName.java
+++ b/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/NotificationName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class NotificationName implements ResourceName {
   private static final PathTemplate PROJECT_BUCKET_NOTIFICATION =
diff --git a/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/ProjectName.java b/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/ProjectName.java
index 813ee0879415..790851e53aa8 100644
--- a/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/ProjectName.java
+++ b/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/ProjectName.java
@@ -25,8 +25,10 @@
 import java.util.Map;
 import java.util.Objects;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
+@NullMarked
 @Generated("by gapic-generator-java")
 public class ProjectName implements ResourceName {
   private static final PathTemplate PROJECT =
diff --git a/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/StorageClient.java b/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/StorageClient.java
index a5dfd3ca29b2..38af59ac85e2 100644
--- a/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/StorageClient.java
+++ b/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/StorageClient.java
@@ -41,6 +41,7 @@
 import java.util.List;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -667,6 +668,7 @@
  *
  * <p>Please refer to the GitHub repository's samples for more quickstart code snippets.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class StorageClient implements BackgroundResource {
   private final StorageSettings settings;
diff --git a/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/StorageSettings.java b/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/StorageSettings.java
index 15e9e7d78cfd..14f6bcbea995 100644
--- a/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/StorageSettings.java
+++ b/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/StorageSettings.java
@@ -44,6 +44,7 @@
 import java.io.IOException;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -94,6 +95,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class StorageSettings extends ClientSettings<StorageSettings> {
 
diff --git a/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/stub/GrpcStorageCallableFactory.java b/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/stub/GrpcStorageCallableFactory.java
index 272e2c8c22c6..423c5d864576 100644
--- a/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/stub/GrpcStorageCallableFactory.java
+++ b/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/stub/GrpcStorageCallableFactory.java
@@ -34,6 +34,7 @@
 import com.google.longrunning.Operation;
 import com.google.longrunning.stub.OperationsStub;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -41,6 +42,7 @@
  *
  * <p>This class is for advanced usage.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcStorageCallableFactory implements GrpcStubCallableFactory {
 
diff --git a/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/stub/GrpcStorageStub.java b/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/stub/GrpcStorageStub.java
index 5335577783cd..bc6ce0b29f70 100644
--- a/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/stub/GrpcStorageStub.java
+++ b/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/stub/GrpcStorageStub.java
@@ -87,6 +87,7 @@
 import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -94,6 +95,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public class GrpcStorageStub extends StorageStub {
   private static final MethodDescriptor<DeleteBucketRequest, Empty> deleteBucketMethodDescriptor =
diff --git a/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/stub/StorageStub.java b/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/stub/StorageStub.java
index f02424e45e16..f68895ed8f02 100644
--- a/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/stub/StorageStub.java
+++ b/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/stub/StorageStub.java
@@ -75,6 +75,7 @@
 import com.google.storage.v2.WriteObjectRequest;
 import com.google.storage.v2.WriteObjectResponse;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -82,6 +83,7 @@
  *
  * <p>This class is for advanced usage and reflects the underlying API directly.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 public abstract class StorageStub implements BackgroundResource {
 
diff --git a/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/stub/StorageStubSettings.java b/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/stub/StorageStubSettings.java
index 1cb752596388..83dd99d89c31 100644
--- a/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/stub/StorageStubSettings.java
+++ b/sdk-platform-java/test/integration/goldens/storage/src/com/google/storage/v2/stub/StorageStubSettings.java
@@ -103,6 +103,7 @@
 import java.time.Duration;
 import java.util.List;
 import javax.annotation.Generated;
+import org.jspecify.annotations.NullMarked;
 
 // AUTO-GENERATED DOCUMENTATION AND CLASS.
 /**
@@ -153,6 +154,7 @@
  * Guide](https://docs.cloud.google.com/java/docs/client-retries) for additional support in setting
  * retries.
  */
+@NullMarked
 @Generated("by gapic-generator-java")
 @SuppressWarnings("CanonicalDuration")
 public class StorageStubSettings extends StubSettings<StorageStubSettings> {