diff --git a/google-cloud-iamcredentials/src/main/java/com/google/cloud/iam/credentials/v1/IamCredentialsSettings.java b/google-cloud-iamcredentials/src/main/java/com/google/cloud/iam/credentials/v1/IamCredentialsSettings.java
index f1e93b62..a70f3829 100644
--- a/google-cloud-iamcredentials/src/main/java/com/google/cloud/iam/credentials/v1/IamCredentialsSettings.java
+++ b/google-cloud-iamcredentials/src/main/java/com/google/cloud/iam/credentials/v1/IamCredentialsSettings.java
@@ -174,14 +174,13 @@ public IamCredentialsStubSettings.Builder getStubSettingsBuilder() {
       return ((IamCredentialsStubSettings.Builder) getStubSettings());
     }
 
-    // NEXT_MAJOR_VER: remove 'throws Exception'.
     /**
      * Applies the given settings updater function to all of the unary API methods in this service.
      *
      * <p>Note: This method does not support applying settings to streaming methods.
      */
     public Builder applyToAllUnaryMethods(
-        ApiFunction<UnaryCallSettings.Builder<?, ?>, Void> settingsUpdater) throws Exception {
+        ApiFunction<UnaryCallSettings.Builder<?, ?>, Void> settingsUpdater) {
       super.applyToAllUnaryMethods(
           getStubSettingsBuilder().unaryMethodSettingsBuilders(), settingsUpdater);
       return this;
diff --git a/google-cloud-iamcredentials/src/main/java/com/google/cloud/iam/credentials/v1/stub/GrpcIamCredentialsStub.java b/google-cloud-iamcredentials/src/main/java/com/google/cloud/iam/credentials/v1/stub/GrpcIamCredentialsStub.java
index 48731cd5..0554619e 100644
--- a/google-cloud-iamcredentials/src/main/java/com/google/cloud/iam/credentials/v1/stub/GrpcIamCredentialsStub.java
+++ b/google-cloud-iamcredentials/src/main/java/com/google/cloud/iam/credentials/v1/stub/GrpcIamCredentialsStub.java
@@ -21,7 +21,6 @@
 import com.google.api.gax.grpc.GrpcCallSettings;
 import com.google.api.gax.grpc.GrpcStubCallableFactory;
 import com.google.api.gax.rpc.ClientContext;
-import com.google.api.gax.rpc.RequestParamsExtractor;
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.cloud.iam.credentials.v1.GenerateAccessTokenRequest;
 import com.google.cloud.iam.credentials.v1.GenerateAccessTokenResponse;
@@ -36,7 +35,6 @@
 import io.grpc.MethodDescriptor;
 import io.grpc.protobuf.ProtoUtils;
 import java.io.IOException;
-import java.util.Map;
 import java.util.concurrent.TimeUnit;
 import javax.annotation.Generated;
 
@@ -143,13 +141,10 @@ protected GrpcIamCredentialsStub(
             GrpcCallSettings.<GenerateAccessTokenRequest, GenerateAccessTokenResponse>newBuilder()
                 .setMethodDescriptor(generateAccessTokenMethodDescriptor)
                 .setParamsExtractor(
-                    new RequestParamsExtractor<GenerateAccessTokenRequest>() {
-                      @Override
-                      public Map<String, String> extract(GenerateAccessTokenRequest request) {
-                        ImmutableMap.Builder<String, String> params = ImmutableMap.builder();
-                        params.put("name", String.valueOf(request.getName()));
-                        return params.build();
-                      }
+                    request -> {
+                      ImmutableMap.Builder<String, String> params = ImmutableMap.builder();
+                      params.put("name", String.valueOf(request.getName()));
+                      return params.build();
                     })
                 .build();
     GrpcCallSettings<GenerateIdTokenRequest, GenerateIdTokenResponse>
@@ -157,39 +152,30 @@ public Map<String, String> extract(GenerateAccessTokenRequest request) {
             GrpcCallSettings.<GenerateIdTokenRequest, GenerateIdTokenResponse>newBuilder()
                 .setMethodDescriptor(generateIdTokenMethodDescriptor)
                 .setParamsExtractor(
-                    new RequestParamsExtractor<GenerateIdTokenRequest>() {
-                      @Override
-                      public Map<String, String> extract(GenerateIdTokenRequest request) {
-                        ImmutableMap.Builder<String, String> params = ImmutableMap.builder();
-                        params.put("name", String.valueOf(request.getName()));
-                        return params.build();
-                      }
+                    request -> {
+                      ImmutableMap.Builder<String, String> params = ImmutableMap.builder();
+                      params.put("name", String.valueOf(request.getName()));
+                      return params.build();
                     })
                 .build();
     GrpcCallSettings<SignBlobRequest, SignBlobResponse> signBlobTransportSettings =
         GrpcCallSettings.<SignBlobRequest, SignBlobResponse>newBuilder()
             .setMethodDescriptor(signBlobMethodDescriptor)
             .setParamsExtractor(
-                new RequestParamsExtractor<SignBlobRequest>() {
-                  @Override
-                  public Map<String, String> extract(SignBlobRequest request) {
-                    ImmutableMap.Builder<String, String> params = ImmutableMap.builder();
-                    params.put("name", String.valueOf(request.getName()));
-                    return params.build();
-                  }
+                request -> {
+                  ImmutableMap.Builder<String, String> params = ImmutableMap.builder();
+                  params.put("name", String.valueOf(request.getName()));
+                  return params.build();
                 })
             .build();
     GrpcCallSettings<SignJwtRequest, SignJwtResponse> signJwtTransportSettings =
         GrpcCallSettings.<SignJwtRequest, SignJwtResponse>newBuilder()
             .setMethodDescriptor(signJwtMethodDescriptor)
             .setParamsExtractor(
-                new RequestParamsExtractor<SignJwtRequest>() {
-                  @Override
-                  public Map<String, String> extract(SignJwtRequest request) {
-                    ImmutableMap.Builder<String, String> params = ImmutableMap.builder();
-                    params.put("name", String.valueOf(request.getName()));
-                    return params.build();
-                  }
+                request -> {
+                  ImmutableMap.Builder<String, String> params = ImmutableMap.builder();
+                  params.put("name", String.valueOf(request.getName()));
+                  return params.build();
                 })
             .build();
 
@@ -239,7 +225,13 @@ public UnaryCallable<SignJwtRequest, SignJwtResponse> signJwtCallable() {
 
   @Override
   public final void close() {
-    shutdown();
+    try {
+      backgroundResources.close();
+    } catch (RuntimeException e) {
+      throw e;
+    } catch (Exception e) {
+      throw new IllegalStateException("Failed to close resource", e);
+    }
   }
 
   @Override
diff --git a/google-cloud-iamcredentials/src/main/java/com/google/cloud/iam/credentials/v1/stub/IamCredentialsStubSettings.java b/google-cloud-iamcredentials/src/main/java/com/google/cloud/iam/credentials/v1/stub/IamCredentialsStubSettings.java
index 7a4cd497..45338c51 100644
--- a/google-cloud-iamcredentials/src/main/java/com/google/cloud/iam/credentials/v1/stub/IamCredentialsStubSettings.java
+++ b/google-cloud-iamcredentials/src/main/java/com/google/cloud/iam/credentials/v1/stub/IamCredentialsStubSettings.java
@@ -312,14 +312,13 @@ private static Builder initDefaults(Builder builder) {
       return builder;
     }
 
-    // NEXT_MAJOR_VER: remove 'throws Exception'.
     /**
      * Applies the given settings updater function to all of the unary API methods in this service.
      *
      * <p>Note: This method does not support applying settings to streaming methods.
      */
     public Builder applyToAllUnaryMethods(
-        ApiFunction<UnaryCallSettings.Builder<?, ?>, Void> settingsUpdater) throws Exception {
+        ApiFunction<UnaryCallSettings.Builder<?, ?>, Void> settingsUpdater) {
       super.applyToAllUnaryMethods(unaryMethodSettingsBuilders, settingsUpdater);
       return this;
     }
diff --git a/synth.metadata b/synth.metadata
index 6df25599..453b4f32 100644
--- a/synth.metadata
+++ b/synth.metadata
@@ -11,8 +11,8 @@
       "git": {
         "name": "googleapis",
         "remote": "https://github.com/googleapis/googleapis.git",
-        "sha": "551681f25e36b11829e87e580281350461f4f3f5",
-        "internalRef": "379784268"
+        "sha": "d9eaf41de44d953458b18712a3f240bb4c564e48",
+        "internalRef": "388535346"
       }
     },
     {