diff --git a/benchmarks/src/main/java/io/grpc/benchmarks/qps/QpsClient.java b/benchmarks/src/main/java/io/grpc/benchmarks/qps/QpsClient.java
index 08d2b8d156..bc73b2c710 100644
--- a/benchmarks/src/main/java/io/grpc/benchmarks/qps/QpsClient.java
+++ b/benchmarks/src/main/java/io/grpc/benchmarks/qps/QpsClient.java
@@ -38,7 +38,6 @@ import static io.grpc.testing.integration.Util.loadCert;
 import static java.lang.Math.max;
 
 import com.google.common.base.Preconditions;
-import com.google.common.util.concurrent.MoreExecutors;
 
 import grpc.testing.Qpstest.PayloadType;
 import grpc.testing.TestServiceGrpc;
@@ -58,7 +57,6 @@ import java.io.IOException;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
 import java.util.ArrayList;
-import java.util.IllegalFormatException;
 import java.util.List;
 import java.util.concurrent.CancellationException;
 import java.util.concurrent.ExecutionException;
diff --git a/benchmarks/src/main/java/io/grpc/benchmarks/qps/QpsServer.java b/benchmarks/src/main/java/io/grpc/benchmarks/qps/QpsServer.java
index 4750815637..1d86ea35a4 100644
--- a/benchmarks/src/main/java/io/grpc/benchmarks/qps/QpsServer.java
+++ b/benchmarks/src/main/java/io/grpc/benchmarks/qps/QpsServer.java
@@ -45,9 +45,7 @@ import static grpc.testing.Qpstest.StreamingOutputCallRequest;
 import static grpc.testing.Qpstest.StreamingOutputCallResponse;
 import static io.grpc.testing.integration.Util.loadCert;
 import static io.grpc.testing.integration.Util.pickUnusedPort;
-import static java.lang.Math.max;
 
-import com.google.common.util.concurrent.MoreExecutors;
 import com.google.protobuf.ByteString;
 
 import grpc.testing.Qpstest;
@@ -56,8 +54,6 @@ import io.grpc.ServerImpl;
 import io.grpc.Status;
 import io.grpc.stub.StreamObserver;
 import io.grpc.transport.netty.NettyServerBuilder;
-import io.netty.channel.EventLoopGroup;
-import io.netty.channel.nio.NioEventLoopGroup;
 import io.netty.handler.ssl.SslContext;
 
 import java.io.File;
diff --git a/checkstyle.xml b/checkstyle.xml
index 941f6f829c..445aff4109 100644
--- a/checkstyle.xml
+++ b/checkstyle.xml
@@ -49,6 +49,7 @@
             <property name="ignorePattern" value="^package.*|^import.*|a href|href|http://|https://|ftp://"/>
         </module>
         <module name="AvoidStarImport"/>
+        <module name="UnusedImports"/>
         <module name="OneTopLevelClass"/>
         <module name="NoLineWrap"/>
         <module name="EmptyBlock">
diff --git a/core/src/test/java/io/grpc/transport/MessageFramerTest.java b/core/src/test/java/io/grpc/transport/MessageFramerTest.java
index 0004bf2af5..f209e8dc53 100644
--- a/core/src/test/java/io/grpc/transport/MessageFramerTest.java
+++ b/core/src/test/java/io/grpc/transport/MessageFramerTest.java
@@ -38,8 +38,6 @@ import static org.mockito.Matchers.eq;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyNoMoreInteractions;
 
-import com.google.common.base.Preconditions;
-
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
diff --git a/integration-testing/src/main/java/io/grpc/testing/integration/AbstractTransportTest.java b/integration-testing/src/main/java/io/grpc/testing/integration/AbstractTransportTest.java
index 8a0fd86205..b8c98f9129 100644
--- a/integration-testing/src/main/java/io/grpc/testing/integration/AbstractTransportTest.java
+++ b/integration-testing/src/main/java/io/grpc/testing/integration/AbstractTransportTest.java
@@ -71,9 +71,7 @@ import org.junit.Before;
 import org.junit.Test;
 import org.mockito.ArgumentCaptor;
 
-import java.util.ArrayList;
 import java.util.Arrays;
-import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.ArrayBlockingQueue;
 import java.util.concurrent.Executors;
diff --git a/integration-testing/src/main/java/io/grpc/testing/integration/TestServiceClient.java b/integration-testing/src/main/java/io/grpc/testing/integration/TestServiceClient.java
index 4e7dbf95cf..af21651b54 100644
--- a/integration-testing/src/main/java/io/grpc/testing/integration/TestServiceClient.java
+++ b/integration-testing/src/main/java/io/grpc/testing/integration/TestServiceClient.java
@@ -37,13 +37,10 @@ import io.grpc.transport.netty.NettyChannelBuilder;
 import io.grpc.transport.okhttp.OkHttpChannelBuilder;
 import io.netty.handler.ssl.SslContext;
 
-import java.io.File;
 import java.net.InetAddress;
 import java.net.InetSocketAddress;
 import java.net.UnknownHostException;
 
-import javax.net.ssl.SSLException;
-
 /**
  * Application that starts a client for the {@link TestServiceGrpc.TestService} and runs through a
  * series of tests.
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 4be854927e..8fbcde0bd4 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
@@ -36,7 +36,6 @@ import com.google.protobuf.ByteString;
 import com.google.protobuf.EmptyProtos;
 
 import io.grpc.stub.StreamObserver;
-import io.grpc.testing.integration.Messages.Payload;
 import io.grpc.testing.integration.Messages.PayloadType;
 import io.grpc.testing.integration.Messages.ResponseParameters;
 import io.grpc.testing.integration.Messages.SimpleRequest;
diff --git a/integration-testing/src/main/java/io/grpc/testing/integration/TestServiceServer.java b/integration-testing/src/main/java/io/grpc/testing/integration/TestServiceServer.java
index ac20d7a7b3..8e4713ea5f 100644
--- a/integration-testing/src/main/java/io/grpc/testing/integration/TestServiceServer.java
+++ b/integration-testing/src/main/java/io/grpc/testing/integration/TestServiceServer.java
@@ -39,7 +39,6 @@ import io.grpc.testing.TestUtils;
 import io.grpc.transport.netty.NettyServerBuilder;
 import io.netty.handler.ssl.SslContext;
 
-import java.io.File;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
diff --git a/integration-testing/src/main/java/io/grpc/testing/integration/Util.java b/integration-testing/src/main/java/io/grpc/testing/integration/Util.java
index bd367a1802..7df9ea1320 100644
--- a/integration-testing/src/main/java/io/grpc/testing/integration/Util.java
+++ b/integration-testing/src/main/java/io/grpc/testing/integration/Util.java
@@ -40,7 +40,6 @@ import org.junit.Assert;
 
 import java.io.BufferedWriter;
 import java.io.File;
-import java.io.FileOutputStream;
 import java.io.FileWriter;
 import java.io.InputStream;
 import java.io.IOException;
diff --git a/integration-testing/src/test/java/io/grpc/testing/integration/Http2NettyTest.java b/integration-testing/src/test/java/io/grpc/testing/integration/Http2NettyTest.java
index c669d36bb4..d864ad0101 100644
--- a/integration-testing/src/test/java/io/grpc/testing/integration/Http2NettyTest.java
+++ b/integration-testing/src/test/java/io/grpc/testing/integration/Http2NettyTest.java
@@ -32,7 +32,6 @@
 package io.grpc.testing.integration;
 
 import io.grpc.ChannelImpl;
-import io.grpc.transport.netty.NegotiationType;
 import io.grpc.transport.netty.NettyChannelBuilder;
 import io.grpc.transport.netty.NettyServerBuilder;
 import io.netty.handler.ssl.SslContext;
diff --git a/netty/src/main/java/io/grpc/transport/netty/NettyServerBuilder.java b/netty/src/main/java/io/grpc/transport/netty/NettyServerBuilder.java
index 38857794fd..e54f566768 100644
--- a/netty/src/main/java/io/grpc/transport/netty/NettyServerBuilder.java
+++ b/netty/src/main/java/io/grpc/transport/netty/NettyServerBuilder.java
@@ -37,7 +37,6 @@ import com.google.common.util.concurrent.Service;
 
 import io.grpc.AbstractServerBuilder;
 import io.grpc.HandlerRegistry;
-import io.grpc.ServerImpl;
 import io.grpc.SharedResourceHolder;
 import io.grpc.transport.ServerListener;
 import io.netty.channel.EventLoopGroup;
diff --git a/stub/src/main/java/io/grpc/stub/Calls.java b/stub/src/main/java/io/grpc/stub/Calls.java
index ec0b2341f6..a62c21ef45 100644
--- a/stub/src/main/java/io/grpc/stub/Calls.java
+++ b/stub/src/main/java/io/grpc/stub/Calls.java
@@ -47,7 +47,6 @@ import java.util.Iterator;
 import java.util.NoSuchElementException;
 import java.util.concurrent.ArrayBlockingQueue;
 import java.util.concurrent.BlockingQueue;
-import java.util.concurrent.CancellationException;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;