diff --git a/compiler/src/test/proto/test.proto b/compiler/src/test/proto/test.proto
index c448036278..ba4938df9e 100644
--- a/compiler/src/test/proto/test.proto
+++ b/compiler/src/test/proto/test.proto
@@ -1,5 +1,5 @@
 // A simple service definition for testing the protoc plugin.
-syntax = "proto2";
+syntax = "proto3";
 
 package grpc.testing;
 
diff --git a/integration-testing/src/main/java/io/grpc/testing/integration/TestServiceImpl.java b/integration-testing/src/main/java/io/grpc/testing/integration/TestServiceImpl.java
index ed89eb8668..0261d14201 100644
--- a/integration-testing/src/main/java/io/grpc/testing/integration/TestServiceImpl.java
+++ b/integration-testing/src/main/java/io/grpc/testing/integration/TestServiceImpl.java
@@ -129,10 +129,7 @@ public class TestServiceImpl implements TestServiceGrpc.TestService {
 
       @Override
       public void onValue(StreamingInputCallRequest message) {
-        Payload payload = message.getPayload();
-        if (payload.hasBody()) {
-          totalPayloadSize += payload.getBody().size();
-        }
+        totalPayloadSize += message.getPayload().getBody().size();
       }
 
       @Override
@@ -320,8 +317,7 @@ public class TestServiceImpl implements TestServiceGrpc.TestService {
     int offset = 0;
     boolean compressable = compressableResponse(request.getResponseType());
     for (ResponseParameters params : request.getResponseParametersList()) {
-      int interval = params.hasIntervalUs() ? params.getIntervalUs() : 0;
-      chunkQueue.add(new Chunk(interval, offset, params.getSize(), compressable));
+      chunkQueue.add(new Chunk(params.getIntervalUs(), offset, params.getSize(), compressable));
 
       // Increment the offset past this chunk.
       // Both buffers need to be circular.
diff --git a/integration-testing/src/main/proto/io/grpc/testing/integration/message_set.proto b/integration-testing/src/main/proto/io/grpc/testing/integration/message_set.proto
deleted file mode 100644
index bca0ec25ce..0000000000
--- a/integration-testing/src/main/proto/io/grpc/testing/integration/message_set.proto
+++ /dev/null
@@ -1,19 +0,0 @@
-//
-// Copyright 2014 Google Inc. All rights reserved.
-//
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file or at
-// https://developers.google.com/open-source/licenses/bsd
-syntax = "proto2";
-
-package proto2.bridge;
-
-option java_outer_classname = "MessageSetProtos";
-option java_multiple_files = true;
-option java_generate_equals_and_hash = true;
-
-message MessageSet {
-  option message_set_wire_format = true;
-  extensions 4 to max;
-}
-
diff --git a/integration-testing/src/main/proto/io/grpc/testing/integration/messages.proto b/integration-testing/src/main/proto/io/grpc/testing/integration/messages.proto
index 52e2e53b3c..471d837557 100644
--- a/integration-testing/src/main/proto/io/grpc/testing/integration/messages.proto
+++ b/integration-testing/src/main/proto/io/grpc/testing/integration/messages.proto
@@ -4,12 +4,10 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file or at
 // https://developers.google.com/open-source/licenses/bsd
-syntax = "proto2";
+syntax = "proto3";
 
 package stubby.testing;
 
-import "io/grpc/testing/integration/message_set.proto";
-
 option java_package = "io.grpc.testing.integration";
 
 // The type of payload that should be returned.
@@ -56,10 +54,6 @@ message SimpleResponse {
 }
 
 message SimpleContext {
-  // Register MessageSet extension.
-  extend proto2.bridge.MessageSet {
-    optional SimpleContext message_set_extension = 71139615;
-  }
   optional string value = 1;
 }