diff --git a/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1/DocumentProcessorServiceSettings.java b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1/DocumentProcessorServiceSettings.java
index 77513d68..86198bfd 100644
--- a/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1/DocumentProcessorServiceSettings.java
+++ b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1/DocumentProcessorServiceSettings.java
@@ -187,14 +187,13 @@ public DocumentProcessorServiceStubSettings.Builder getStubSettingsBuilder() {
       return ((DocumentProcessorServiceStubSettings.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-document-ai/src/main/java/com/google/cloud/documentai/v1/stub/DocumentProcessorServiceStubSettings.java b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1/stub/DocumentProcessorServiceStubSettings.java
index 4b82b33e..48029f1d 100644
--- a/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1/stub/DocumentProcessorServiceStubSettings.java
+++ b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1/stub/DocumentProcessorServiceStubSettings.java
@@ -377,14 +377,13 @@ 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/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1/stub/GrpcDocumentProcessorServiceStub.java b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1/stub/GrpcDocumentProcessorServiceStub.java
index a249abdd..70819895 100644
--- a/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1/stub/GrpcDocumentProcessorServiceStub.java
+++ b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1/stub/GrpcDocumentProcessorServiceStub.java
@@ -22,7 +22,6 @@
 import com.google.api.gax.grpc.GrpcStubCallableFactory;
 import com.google.api.gax.rpc.ClientContext;
 import com.google.api.gax.rpc.OperationCallable;
-import com.google.api.gax.rpc.RequestParamsExtractor;
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.cloud.documentai.v1.BatchProcessMetadata;
 import com.google.cloud.documentai.v1.BatchProcessRequest;
@@ -38,7 +37,6 @@
 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;
 
@@ -139,40 +137,30 @@ protected GrpcDocumentProcessorServiceStub(
         GrpcCallSettings.<ProcessRequest, ProcessResponse>newBuilder()
             .setMethodDescriptor(processDocumentMethodDescriptor)
             .setParamsExtractor(
-                new RequestParamsExtractor<ProcessRequest>() {
-                  @Override
-                  public Map<String, String> extract(ProcessRequest 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<BatchProcessRequest, Operation> batchProcessDocumentsTransportSettings =
         GrpcCallSettings.<BatchProcessRequest, Operation>newBuilder()
             .setMethodDescriptor(batchProcessDocumentsMethodDescriptor)
             .setParamsExtractor(
-                new RequestParamsExtractor<BatchProcessRequest>() {
-                  @Override
-                  public Map<String, String> extract(BatchProcessRequest 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<ReviewDocumentRequest, Operation> reviewDocumentTransportSettings =
         GrpcCallSettings.<ReviewDocumentRequest, Operation>newBuilder()
             .setMethodDescriptor(reviewDocumentMethodDescriptor)
             .setParamsExtractor(
-                new RequestParamsExtractor<ReviewDocumentRequest>() {
-                  @Override
-                  public Map<String, String> extract(ReviewDocumentRequest request) {
-                    ImmutableMap.Builder<String, String> params = ImmutableMap.builder();
-                    params.put(
-                        "human_review_config", String.valueOf(request.getHumanReviewConfig()));
-                    return params.build();
-                  }
+                request -> {
+                  ImmutableMap.Builder<String, String> params = ImmutableMap.builder();
+                  params.put("human_review_config", String.valueOf(request.getHumanReviewConfig()));
+                  return params.build();
                 })
             .build();
 
diff --git a/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta1/DocumentUnderstandingServiceSettings.java b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta1/DocumentUnderstandingServiceSettings.java
index dac93c82..76f4afe4 100644
--- a/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta1/DocumentUnderstandingServiceSettings.java
+++ b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta1/DocumentUnderstandingServiceSettings.java
@@ -172,14 +172,13 @@ public DocumentUnderstandingServiceStubSettings.Builder getStubSettingsBuilder()
       return ((DocumentUnderstandingServiceStubSettings.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-document-ai/src/main/java/com/google/cloud/documentai/v1beta1/stub/DocumentUnderstandingServiceStubSettings.java b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta1/stub/DocumentUnderstandingServiceStubSettings.java
index 920eec06..54376f0e 100644
--- a/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta1/stub/DocumentUnderstandingServiceStubSettings.java
+++ b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta1/stub/DocumentUnderstandingServiceStubSettings.java
@@ -303,14 +303,13 @@ 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/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta1/stub/GrpcDocumentUnderstandingServiceStub.java b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta1/stub/GrpcDocumentUnderstandingServiceStub.java
index 461c8666..58a06e43 100644
--- a/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta1/stub/GrpcDocumentUnderstandingServiceStub.java
+++ b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta1/stub/GrpcDocumentUnderstandingServiceStub.java
@@ -23,7 +23,6 @@
 import com.google.api.gax.grpc.GrpcStubCallableFactory;
 import com.google.api.gax.rpc.ClientContext;
 import com.google.api.gax.rpc.OperationCallable;
-import com.google.api.gax.rpc.RequestParamsExtractor;
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.cloud.documentai.v1beta1.BatchProcessDocumentsRequest;
 import com.google.cloud.documentai.v1beta1.BatchProcessDocumentsResponse;
@@ -34,7 +33,6 @@
 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;
 
@@ -116,13 +114,10 @@ protected GrpcDocumentUnderstandingServiceStub(
             GrpcCallSettings.<BatchProcessDocumentsRequest, Operation>newBuilder()
                 .setMethodDescriptor(batchProcessDocumentsMethodDescriptor)
                 .setParamsExtractor(
-                    new RequestParamsExtractor<BatchProcessDocumentsRequest>() {
-                      @Override
-                      public Map<String, String> extract(BatchProcessDocumentsRequest request) {
-                        ImmutableMap.Builder<String, String> params = ImmutableMap.builder();
-                        params.put("parent", String.valueOf(request.getParent()));
-                        return params.build();
-                      }
+                    request -> {
+                      ImmutableMap.Builder<String, String> params = ImmutableMap.builder();
+                      params.put("parent", String.valueOf(request.getParent()));
+                      return params.build();
                     })
                 .build();
 
diff --git a/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta2/DocumentUnderstandingServiceSettings.java b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta2/DocumentUnderstandingServiceSettings.java
index 8e270c99..198bb1fd 100644
--- a/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta2/DocumentUnderstandingServiceSettings.java
+++ b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta2/DocumentUnderstandingServiceSettings.java
@@ -177,14 +177,13 @@ public DocumentUnderstandingServiceStubSettings.Builder getStubSettingsBuilder()
       return ((DocumentUnderstandingServiceStubSettings.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-document-ai/src/main/java/com/google/cloud/documentai/v1beta2/stub/DocumentUnderstandingServiceStubSettings.java b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta2/stub/DocumentUnderstandingServiceStubSettings.java
index 48e93174..7ee2c091 100644
--- a/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta2/stub/DocumentUnderstandingServiceStubSettings.java
+++ b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta2/stub/DocumentUnderstandingServiceStubSettings.java
@@ -323,14 +323,13 @@ 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/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta2/stub/GrpcDocumentUnderstandingServiceStub.java b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta2/stub/GrpcDocumentUnderstandingServiceStub.java
index 5db483f1..23690e5c 100644
--- a/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta2/stub/GrpcDocumentUnderstandingServiceStub.java
+++ b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta2/stub/GrpcDocumentUnderstandingServiceStub.java
@@ -23,7 +23,6 @@
 import com.google.api.gax.grpc.GrpcStubCallableFactory;
 import com.google.api.gax.rpc.ClientContext;
 import com.google.api.gax.rpc.OperationCallable;
-import com.google.api.gax.rpc.RequestParamsExtractor;
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.cloud.documentai.v1beta2.BatchProcessDocumentsRequest;
 import com.google.cloud.documentai.v1beta2.BatchProcessDocumentsResponse;
@@ -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;
 
@@ -130,26 +128,20 @@ protected GrpcDocumentUnderstandingServiceStub(
             GrpcCallSettings.<BatchProcessDocumentsRequest, Operation>newBuilder()
                 .setMethodDescriptor(batchProcessDocumentsMethodDescriptor)
                 .setParamsExtractor(
-                    new RequestParamsExtractor<BatchProcessDocumentsRequest>() {
-                      @Override
-                      public Map<String, String> extract(BatchProcessDocumentsRequest request) {
-                        ImmutableMap.Builder<String, String> params = ImmutableMap.builder();
-                        params.put("parent", String.valueOf(request.getParent()));
-                        return params.build();
-                      }
+                    request -> {
+                      ImmutableMap.Builder<String, String> params = ImmutableMap.builder();
+                      params.put("parent", String.valueOf(request.getParent()));
+                      return params.build();
                     })
                 .build();
     GrpcCallSettings<ProcessDocumentRequest, Document> processDocumentTransportSettings =
         GrpcCallSettings.<ProcessDocumentRequest, Document>newBuilder()
             .setMethodDescriptor(processDocumentMethodDescriptor)
             .setParamsExtractor(
-                new RequestParamsExtractor<ProcessDocumentRequest>() {
-                  @Override
-                  public Map<String, String> extract(ProcessDocumentRequest request) {
-                    ImmutableMap.Builder<String, String> params = ImmutableMap.builder();
-                    params.put("parent", String.valueOf(request.getParent()));
-                    return params.build();
-                  }
+                request -> {
+                  ImmutableMap.Builder<String, String> params = ImmutableMap.builder();
+                  params.put("parent", String.valueOf(request.getParent()));
+                  return params.build();
                 })
             .build();
 
diff --git a/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta3/DocumentProcessorServiceClient.java b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta3/DocumentProcessorServiceClient.java
index 5cf936fd..de602612 100644
--- a/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta3/DocumentProcessorServiceClient.java
+++ b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta3/DocumentProcessorServiceClient.java
@@ -16,7 +16,6 @@
 
 package com.google.cloud.documentai.v1beta3;
 
-import com.google.api.core.ApiFunction;
 import com.google.api.core.ApiFuture;
 import com.google.api.core.ApiFutures;
 import com.google.api.core.BetaApi;
@@ -1247,12 +1246,7 @@ public static ApiFuture<ListProcessorsPagedResponse> createAsync(
           ListProcessorsPage.createEmptyPage().createPageAsync(context, futureResponse);
       return ApiFutures.transform(
           futurePage,
-          new ApiFunction<ListProcessorsPage, ListProcessorsPagedResponse>() {
-            @Override
-            public ListProcessorsPagedResponse apply(ListProcessorsPage input) {
-              return new ListProcessorsPagedResponse(input);
-            }
-          },
+          input -> new ListProcessorsPagedResponse(input),
           MoreExecutors.directExecutor());
     }
 
diff --git a/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta3/DocumentProcessorServiceSettings.java b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta3/DocumentProcessorServiceSettings.java
index 1ef54e0c..031e3e18 100644
--- a/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta3/DocumentProcessorServiceSettings.java
+++ b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta3/DocumentProcessorServiceSettings.java
@@ -248,14 +248,13 @@ public DocumentProcessorServiceStubSettings.Builder getStubSettingsBuilder() {
       return ((DocumentProcessorServiceStubSettings.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-document-ai/src/main/java/com/google/cloud/documentai/v1beta3/stub/DocumentProcessorServiceStubSettings.java b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta3/stub/DocumentProcessorServiceStubSettings.java
index 8939a3d8..e3db1c12 100644
--- a/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta3/stub/DocumentProcessorServiceStubSettings.java
+++ b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta3/stub/DocumentProcessorServiceStubSettings.java
@@ -696,14 +696,13 @@ 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/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta3/stub/GrpcDocumentProcessorServiceStub.java b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta3/stub/GrpcDocumentProcessorServiceStub.java
index c67a5b93..e2b1cb69 100644
--- a/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta3/stub/GrpcDocumentProcessorServiceStub.java
+++ b/google-cloud-document-ai/src/main/java/com/google/cloud/documentai/v1beta3/stub/GrpcDocumentProcessorServiceStub.java
@@ -25,7 +25,6 @@
 import com.google.api.gax.grpc.GrpcStubCallableFactory;
 import com.google.api.gax.rpc.ClientContext;
 import com.google.api.gax.rpc.OperationCallable;
-import com.google.api.gax.rpc.RequestParamsExtractor;
 import com.google.api.gax.rpc.UnaryCallable;
 import com.google.cloud.documentai.v1beta3.BatchProcessMetadata;
 import com.google.cloud.documentai.v1beta3.BatchProcessRequest;
@@ -56,7 +55,6 @@
 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;
 
@@ -243,26 +241,20 @@ protected GrpcDocumentProcessorServiceStub(
         GrpcCallSettings.<ProcessRequest, ProcessResponse>newBuilder()
             .setMethodDescriptor(processDocumentMethodDescriptor)
             .setParamsExtractor(
-                new RequestParamsExtractor<ProcessRequest>() {
-                  @Override
-                  public Map<String, String> extract(ProcessRequest 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<BatchProcessRequest, Operation> batchProcessDocumentsTransportSettings =
         GrpcCallSettings.<BatchProcessRequest, Operation>newBuilder()
             .setMethodDescriptor(batchProcessDocumentsMethodDescriptor)
             .setParamsExtractor(
-                new RequestParamsExtractor<BatchProcessRequest>() {
-                  @Override
-                  public Map<String, String> extract(BatchProcessRequest 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<FetchProcessorTypesRequest, FetchProcessorTypesResponse>
@@ -270,13 +262,10 @@ public Map<String, String> extract(BatchProcessRequest request) {
             GrpcCallSettings.<FetchProcessorTypesRequest, FetchProcessorTypesResponse>newBuilder()
                 .setMethodDescriptor(fetchProcessorTypesMethodDescriptor)
                 .setParamsExtractor(
-                    new RequestParamsExtractor<FetchProcessorTypesRequest>() {
-                      @Override
-                      public Map<String, String> extract(FetchProcessorTypesRequest request) {
-                        ImmutableMap.Builder<String, String> params = ImmutableMap.builder();
-                        params.put("parent", String.valueOf(request.getParent()));
-                        return params.build();
-                      }
+                    request -> {
+                      ImmutableMap.Builder<String, String> params = ImmutableMap.builder();
+                      params.put("parent", String.valueOf(request.getParent()));
+                      return params.build();
                     })
                 .build();
     GrpcCallSettings<ListProcessorsRequest, ListProcessorsResponse>
@@ -284,79 +273,60 @@ public Map<String, String> extract(FetchProcessorTypesRequest request) {
             GrpcCallSettings.<ListProcessorsRequest, ListProcessorsResponse>newBuilder()
                 .setMethodDescriptor(listProcessorsMethodDescriptor)
                 .setParamsExtractor(
-                    new RequestParamsExtractor<ListProcessorsRequest>() {
-                      @Override
-                      public Map<String, String> extract(ListProcessorsRequest request) {
-                        ImmutableMap.Builder<String, String> params = ImmutableMap.builder();
-                        params.put("parent", String.valueOf(request.getParent()));
-                        return params.build();
-                      }
+                    request -> {
+                      ImmutableMap.Builder<String, String> params = ImmutableMap.builder();
+                      params.put("parent", String.valueOf(request.getParent()));
+                      return params.build();
                     })
                 .build();
     GrpcCallSettings<CreateProcessorRequest, Processor> createProcessorTransportSettings =
         GrpcCallSettings.<CreateProcessorRequest, Processor>newBuilder()
             .setMethodDescriptor(createProcessorMethodDescriptor)
             .setParamsExtractor(
-                new RequestParamsExtractor<CreateProcessorRequest>() {
-                  @Override
-                  public Map<String, String> extract(CreateProcessorRequest request) {
-                    ImmutableMap.Builder<String, String> params = ImmutableMap.builder();
-                    params.put("parent", String.valueOf(request.getParent()));
-                    return params.build();
-                  }
+                request -> {
+                  ImmutableMap.Builder<String, String> params = ImmutableMap.builder();
+                  params.put("parent", String.valueOf(request.getParent()));
+                  return params.build();
                 })
             .build();
     GrpcCallSettings<DeleteProcessorRequest, Operation> deleteProcessorTransportSettings =
         GrpcCallSettings.<DeleteProcessorRequest, Operation>newBuilder()
             .setMethodDescriptor(deleteProcessorMethodDescriptor)
             .setParamsExtractor(
-                new RequestParamsExtractor<DeleteProcessorRequest>() {
-                  @Override
-                  public Map<String, String> extract(DeleteProcessorRequest 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<EnableProcessorRequest, Operation> enableProcessorTransportSettings =
         GrpcCallSettings.<EnableProcessorRequest, Operation>newBuilder()
             .setMethodDescriptor(enableProcessorMethodDescriptor)
             .setParamsExtractor(
-                new RequestParamsExtractor<EnableProcessorRequest>() {
-                  @Override
-                  public Map<String, String> extract(EnableProcessorRequest 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<DisableProcessorRequest, Operation> disableProcessorTransportSettings =
         GrpcCallSettings.<DisableProcessorRequest, Operation>newBuilder()
             .setMethodDescriptor(disableProcessorMethodDescriptor)
             .setParamsExtractor(
-                new RequestParamsExtractor<DisableProcessorRequest>() {
-                  @Override
-                  public Map<String, String> extract(DisableProcessorRequest 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<ReviewDocumentRequest, Operation> reviewDocumentTransportSettings =
         GrpcCallSettings.<ReviewDocumentRequest, Operation>newBuilder()
             .setMethodDescriptor(reviewDocumentMethodDescriptor)
             .setParamsExtractor(
-                new RequestParamsExtractor<ReviewDocumentRequest>() {
-                  @Override
-                  public Map<String, String> extract(ReviewDocumentRequest request) {
-                    ImmutableMap.Builder<String, String> params = ImmutableMap.builder();
-                    params.put(
-                        "human_review_config", String.valueOf(request.getHumanReviewConfig()));
-                    return params.build();
-                  }
+                request -> {
+                  ImmutableMap.Builder<String, String> params = ImmutableMap.builder();
+                  params.put("human_review_config", String.valueOf(request.getHumanReviewConfig()));
+                  return params.build();
                 })
             .build();