diff --git a/remoting/src/main/java/org/apache/rocketmq/remoting/RemotingClientFactory.java b/remoting/src/main/java/org/apache/rocketmq/remoting/RemotingClientFactory.java
index b5e5a91c93c..04534064d1f 100644
--- a/remoting/src/main/java/org/apache/rocketmq/remoting/RemotingClientFactory.java
+++ b/remoting/src/main/java/org/apache/rocketmq/remoting/RemotingClientFactory.java
@@ -17,16 +17,13 @@
 package org.apache.rocketmq.remoting;
 
 import java.util.Map;
-import org.apache.rocketmq.logging.InternalLogger;
-import org.apache.rocketmq.logging.InternalLoggerFactory;
-import org.apache.rocketmq.remoting.common.RemotingHelper;
 import org.apache.rocketmq.remoting.common.RemotingUtil;
 import org.apache.rocketmq.remoting.util.ServiceProvider;
 
 public class RemotingClientFactory {
     private static RemotingClientFactory instance = new RemotingClientFactory();
 
-    public static RemotingClientFactory getInstance(){
+    public static RemotingClientFactory getInstance() {
         return instance;
     }
 
diff --git a/remoting/src/main/java/org/apache/rocketmq/remoting/RemotingServerFactory.java b/remoting/src/main/java/org/apache/rocketmq/remoting/RemotingServerFactory.java
index 231e19a0e75..7c75e8a58f5 100644
--- a/remoting/src/main/java/org/apache/rocketmq/remoting/RemotingServerFactory.java
+++ b/remoting/src/main/java/org/apache/rocketmq/remoting/RemotingServerFactory.java
@@ -17,9 +17,6 @@
 package org.apache.rocketmq.remoting;
 
 import java.util.Map;
-import org.apache.rocketmq.logging.InternalLogger;
-import org.apache.rocketmq.logging.InternalLoggerFactory;
-import org.apache.rocketmq.remoting.common.RemotingHelper;
 import org.apache.rocketmq.remoting.common.RemotingUtil;
 import org.apache.rocketmq.remoting.util.ServiceProvider;
 
diff --git a/remoting/src/main/java/org/apache/rocketmq/remoting/common/RemotingHelper.java b/remoting/src/main/java/org/apache/rocketmq/remoting/common/RemotingHelper.java
index fd8aa1ed83a..fab19239b2e 100644
--- a/remoting/src/main/java/org/apache/rocketmq/remoting/common/RemotingHelper.java
+++ b/remoting/src/main/java/org/apache/rocketmq/remoting/common/RemotingHelper.java
@@ -17,18 +17,11 @@
 package org.apache.rocketmq.remoting.common;
 
 import io.netty.channel.Channel;
-import org.apache.rocketmq.remoting.exception.RemotingConnectException;
-import org.apache.rocketmq.remoting.exception.RemotingSendRequestException;
-import org.apache.rocketmq.remoting.exception.RemotingTimeoutException;
 import org.apache.rocketmq.logging.InternalLogger;
 import org.apache.rocketmq.logging.InternalLoggerFactory;
-import org.apache.rocketmq.remoting.protocol.RemotingCommand;
-
-import java.io.IOException;
 import java.net.InetSocketAddress;
 import java.net.SocketAddress;
-import java.nio.ByteBuffer;
-import java.nio.channels.SocketChannel;
+
 
 public class RemotingHelper {
     public static final String ROCKETMQ_REMOTING = "RocketmqRemoting";
diff --git a/remoting/src/main/java/org/apache/rocketmq/remoting/netty/CodecHelper.java b/remoting/src/main/java/org/apache/rocketmq/remoting/netty/CodecHelper.java
index 193cd398d33..4ce5cd7abc1 100644
--- a/remoting/src/main/java/org/apache/rocketmq/remoting/netty/CodecHelper.java
+++ b/remoting/src/main/java/org/apache/rocketmq/remoting/netty/CodecHelper.java
@@ -1,3 +1,19 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package org.apache.rocketmq.remoting.netty;
 
 import java.lang.annotation.Annotation;
@@ -10,8 +26,6 @@
 import org.apache.rocketmq.remoting.annotation.CFNotNull;
 import org.apache.rocketmq.remoting.exception.RemotingCommandException;
 import org.apache.rocketmq.remoting.protocol.RemotingCommand;
-import org.apache.rocketmq.remoting.serialize.RemotingSerializable;
-import org.apache.rocketmq.remoting.serialize.RocketMQSerializable;
 import org.apache.rocketmq.remoting.serialize.SerializeType;
 import org.apache.rocketmq.remoting.serialize.Serializer;
 import org.apache.rocketmq.remoting.serialize.SerializerFactory;
diff --git a/remoting/src/main/java/org/apache/rocketmq/remoting/netty/NettyRemotingAbstract.java b/remoting/src/main/java/org/apache/rocketmq/remoting/netty/NettyRemotingAbstract.java
index 1555959b0d3..9adb1fc237a 100644
--- a/remoting/src/main/java/org/apache/rocketmq/remoting/netty/NettyRemotingAbstract.java
+++ b/remoting/src/main/java/org/apache/rocketmq/remoting/netty/NettyRemotingAbstract.java
@@ -296,7 +296,7 @@ public void processResponseCommand(ChannelHandlerContext ctx, RemotingCommand cm
                 responseFuture.release();
             }
         } else {
-            log.warn("receive response, but not matched any request: {}， cmd: {}", RemotingHelper.parseChannelRemoteAddr(ctx.channel()), cmd);
+            log.warn("receive response, but not matched any request: {}, cmd: {}", RemotingHelper.parseChannelRemoteAddr(ctx.channel()), cmd);
         }
     }
 
diff --git a/remoting/src/main/java/org/apache/rocketmq/remoting/transport/http2/Http2ClientImpl.java b/remoting/src/main/java/org/apache/rocketmq/remoting/transport/http2/Http2ClientImpl.java
index fb9e3f8beec..9b278245d95 100644
--- a/remoting/src/main/java/org/apache/rocketmq/remoting/transport/http2/Http2ClientImpl.java
+++ b/remoting/src/main/java/org/apache/rocketmq/remoting/transport/http2/Http2ClientImpl.java
@@ -75,7 +75,7 @@ public Http2ClientImpl(final ClientConfig clientConfig,
         init(clientConfig, channelEventListener);
     }
 
-    public Http2ClientImpl(){
+    public Http2ClientImpl() {
         super();
     }
 
diff --git a/remoting/src/main/java/org/apache/rocketmq/remoting/transport/http2/Http2ServerImpl.java b/remoting/src/main/java/org/apache/rocketmq/remoting/transport/http2/Http2ServerImpl.java
index 3352127d1ce..d1dbcf19278 100644
--- a/remoting/src/main/java/org/apache/rocketmq/remoting/transport/http2/Http2ServerImpl.java
+++ b/remoting/src/main/java/org/apache/rocketmq/remoting/transport/http2/Http2ServerImpl.java
@@ -208,26 +208,23 @@ public void start() {
         final ChannelGroup channels = new DefaultChannelGroup(GlobalEventExecutor.INSTANCE);
         this.serverBootstrap.group(this.bossGroup, this.ioGroup).
             channel(socketChannelClass).childHandler(new ChannelInitializer<SocketChannel>() {
-            @Override
-            public void initChannel(SocketChannel ch) throws Exception {
-                channels.add(ch);
-
-                ChannelPipeline cp = ch.pipeline();
-
-                cp.addLast(ChannelStatisticsHandler.NAME, new ChannelStatisticsHandler(channels));
-
-                cp.addLast(workerGroup,
-                    Http2Handler.newHandler(true),
-                    new NettyEncoder(),
-                    new NettyDecoder(),
-                    new IdleStateHandler(serverConfig.getConnectionChannelReaderIdleSeconds(),
-                        serverConfig.getConnectionChannelWriterIdleSeconds(),
-                        serverConfig.getServerChannelMaxIdleTimeSeconds()),
-                    new NettyConnectManageHandler(),
-                    new NettyServerHandler());
-            }
-        });
+                @Override
+                public void initChannel(SocketChannel ch) throws Exception {
+                    channels.add(ch);
 
+                    ChannelPipeline cp = ch.pipeline();
+                    cp.addLast(ChannelStatisticsHandler.NAME, new ChannelStatisticsHandler(channels));
+                    cp.addLast(workerGroup,
+                        Http2Handler.newHandler(true),
+                        new NettyEncoder(),
+                        new NettyDecoder(),
+                        new IdleStateHandler(serverConfig.getConnectionChannelReaderIdleSeconds(),
+                            serverConfig.getConnectionChannelWriterIdleSeconds(),
+                            serverConfig.getServerChannelMaxIdleTimeSeconds()),
+                        new NettyConnectManageHandler(),
+                        new NettyServerHandler());
+                }
+            });
         applyOptions(serverBootstrap);
 
         ChannelFuture channelFuture = this.serverBootstrap.bind(this.port).syncUninterruptibly();
diff --git a/remoting/src/main/java/org/apache/rocketmq/remoting/util/ServiceProvider.java b/remoting/src/main/java/org/apache/rocketmq/remoting/util/ServiceProvider.java
index 586a846847a..cef31f244d1 100644
--- a/remoting/src/main/java/org/apache/rocketmq/remoting/util/ServiceProvider.java
+++ b/remoting/src/main/java/org/apache/rocketmq/remoting/util/ServiceProvider.java
@@ -19,7 +19,6 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
-import java.util.concurrent.ConcurrentHashMap;
 import org.apache.rocketmq.logging.InternalLogger;
 import org.apache.rocketmq.logging.InternalLoggerFactory;
 import org.apache.rocketmq.remoting.common.RemotingHelper;