diff --git a/src/main/java/com/alipay/remoting/ProtocolCode.java b/src/main/java/com/alipay/remoting/ProtocolCode.java
index 8f27438b..b41c7653 100644
--- a/src/main/java/com/alipay/remoting/ProtocolCode.java
+++ b/src/main/java/com/alipay/remoting/ProtocolCode.java
@@ -70,4 +70,4 @@ public int hashCode() {
     public String toString() {
         return "ProtocolVersion{" + "version=" + Arrays.toString(version) + '}';
     }
-}
\ No newline at end of file
+}
diff --git a/src/main/java/com/alipay/remoting/Url.java b/src/main/java/com/alipay/remoting/Url.java
index 732dc6ae..6bdd1380 100644
--- a/src/main/java/com/alipay/remoting/Url.java
+++ b/src/main/java/com/alipay/remoting/Url.java
@@ -28,7 +28,7 @@
 
 /**
  * URL definition.
- * 
+ *
  * @author xiaomin.cxm
  * @version $Id: Url.java, v 0.1 Mar 11, 2016 6:01:59 PM xiaomin.cxm Exp $
  */
@@ -65,7 +65,7 @@ public class Url {
 
     /**
      * Constructor with originUrl
-     * 
+     *
      * @param originUrl
      */
     protected Url(String originUrl) {
@@ -77,8 +77,8 @@ protected Url(String originUrl) {
      * <ul>
      * <li>Initialize ip:port as {@link Url#originUrl} </li>
      * <li>Initialize {@link Url#originUrl} as {@link Url#uniqueKey} </li>
-     * </ul> 
-     * 
+     * </ul>
+     *
      * @param ip
      * @param port
      */
@@ -91,12 +91,12 @@ public Url(String ip, int port) {
 
     /**
      * Constructor with originUrl, ip and port
-     * 
+     *
      * <ul>
      * <li>Initialize @param originUrl as {@link Url#originUrl} </li>
      * <li>Initialize ip:port as {@link Url#uniqueKey} </li>
-     * </ul> 
-     * 
+     * </ul>
+     *
      * @param originUrl
      * @param ip
      * @param port
@@ -110,13 +110,13 @@ public Url(String originUrl, String ip, int port) {
 
     /**
      * Constructor with originUrl, ip, port and properties
-     * 
+     *
      * <ul>
      * <li>Initialize @param originUrl as {@link Url#originUrl} </li>
      * <li>Initialize ip:port as {@link Url#uniqueKey} </li>
      * <li>Initialize @param properties as {@link Url#properties} </li>
-     * </ul> 
-     * 
+     * </ul>
+     *
      * @param originUrl
      * @param ip
      * @param port
@@ -129,13 +129,13 @@ public Url(String originUrl, String ip, int port, Properties properties) {
 
     /**
      * Constructor with originUrl, ip, port, uniqueKey and properties
-     * 
+     *
      * <ul>
      * <li>Initialize @param originUrl as {@link Url#originUrl} </li>
      * <li>Initialize @param uniqueKey as {@link Url#uniqueKey} </li>
      * <li>Initialize @param properties as {@link Url#properties} </li>
      * </ul>
-     * 
+     *
      * @param originUrl
      * @param ip
      * @param port
@@ -150,7 +150,7 @@ public Url(String originUrl, String ip, int port, String uniqueKey, Properties p
 
     /**
      * Get property value according to property key
-     * 
+     *
      * @param key property key
      * @return property value
      */
@@ -253,7 +253,7 @@ public int hashCode() {
 
     @Override
     public String toString() {
-        StringBuilder sb = new StringBuilder();
+        StringBuilder sb = new StringBuilder(32);
         sb.append("Origin url [").append(this.originUrl).append("], Unique key [")
             .append(this.uniqueKey).append("].");
         return sb.toString();
diff --git a/src/main/java/com/alipay/remoting/rpc/RpcInvokeCallbackListener.java b/src/main/java/com/alipay/remoting/rpc/RpcInvokeCallbackListener.java
index 8020e0d4..f36663a7 100644
--- a/src/main/java/com/alipay/remoting/rpc/RpcInvokeCallbackListener.java
+++ b/src/main/java/com/alipay/remoting/rpc/RpcInvokeCallbackListener.java
@@ -35,7 +35,7 @@
 
 /**
  * Listener which listens the Rpc invoke result, and then invokes the call back.
- * 
+ *
  * @author jiangping
  * @version $Id: RpcInvokeCallbackListener.java, v 0.1 2015-9-30 AM10:36:34 tao Exp $
  */
@@ -53,7 +53,7 @@ public RpcInvokeCallbackListener(String address) {
         this.address = address;
     }
 
-    /** 
+    /**
      * @see com.alipay.remoting.InvokeCallbackListener#onResponse(com.alipay.remoting.InvokeFuture)
      */
     @Override
@@ -80,14 +80,14 @@ class CallbackTask implements Runnable {
         String       remoteAddress;
 
         /**
-         * 
+         *
          */
         public CallbackTask(String remoteAddress, InvokeFuture future) {
             this.remoteAddress = remoteAddress;
             this.future = future;
         }
 
-        /** 
+        /**
          * @see java.lang.Runnable#run()
          */
         @Override
@@ -134,7 +134,7 @@ public void run() {
                                 RpcResponseCommand resp = (RpcResponseCommand) response;
                                 resp.deserialize();
                                 Object ex = resp.getResponseObject();
-                                if (ex != null && ex instanceof Throwable) {
+                                if (ex instanceof Throwable) {
                                     e = new InvokeServerException(msg, (Throwable) ex);
                                 } else {
                                     e = new InvokeServerException(msg);
@@ -191,7 +191,7 @@ public void run() {
         } // end of run
     }
 
-    /** 
+    /**
      * @see com.alipay.remoting.InvokeCallbackListener#getRemoteAddress()
      */
     @Override
diff --git a/src/main/java/com/alipay/remoting/rpc/RpcResponseResolver.java b/src/main/java/com/alipay/remoting/rpc/RpcResponseResolver.java
index 77bf02e0..59c3a638 100644
--- a/src/main/java/com/alipay/remoting/rpc/RpcResponseResolver.java
+++ b/src/main/java/com/alipay/remoting/rpc/RpcResponseResolver.java
@@ -35,7 +35,7 @@
 
 /**
  * Resolve response object from response command.
- * 
+ *
  * @author jiangping
  * @version $Id: RpcResponseResolver.java, v 0.1 2015-10-8 PM2:47:29 tao Exp $
  */
@@ -151,7 +151,7 @@ private static Throwable toThrowable(ResponseCommand responseCommand) throws Cod
         RpcResponseCommand resp = (RpcResponseCommand) responseCommand;
         resp.deserialize();
         Object ex = resp.getResponseObject();
-        if (ex != null && ex instanceof Throwable) {
+        if (ex instanceof Throwable) {
             return (Throwable) ex;
         }
         return null;
diff --git a/src/main/java/com/alipay/remoting/rpc/protocol/AsynMultiInterestUserProcessor.java b/src/main/java/com/alipay/remoting/rpc/protocol/AsyncMultiInterestUserProcessor.java
similarity index 84%
rename from src/main/java/com/alipay/remoting/rpc/protocol/AsynMultiInterestUserProcessor.java
rename to src/main/java/com/alipay/remoting/rpc/protocol/AsyncMultiInterestUserProcessor.java
index fc7e679a..fabde7c8 100644
--- a/src/main/java/com/alipay/remoting/rpc/protocol/AsynMultiInterestUserProcessor.java
+++ b/src/main/java/com/alipay/remoting/rpc/protocol/AsyncMultiInterestUserProcessor.java
@@ -23,11 +23,11 @@
 
 /**
  * Extends this to process user defined request in ASYNC way.<br>
- * If you want process reqeuest in SYNC way, please extends {@link SyncMutiInterestUserProcessor}.
+ * If you want process request in SYNC way, please extends {@link SyncMultiInterestUserProcessor}.
  * @author muyun.cyt (muyun.cyt@antfin.com)  2018/7/5   11:19 AM
  */
-public abstract class AsynMultiInterestUserProcessor<T> extends
-                                                        AbstractMultiInterestUserProcessor<T> {
+public abstract class AsyncMultiInterestUserProcessor<T> extends
+                                                         AbstractMultiInterestUserProcessor<T> {
     /**
      * unsupported here!
      *
@@ -36,7 +36,7 @@ public abstract class AsynMultiInterestUserProcessor<T> extends
     @Override
     public Object handleRequest(BizContext bizCtx, T request) throws Exception {
         throw new UnsupportedOperationException(
-            "SYNC handle request is unsupported in AsynMultiInterestUserProcessor!");
+            "SYNC handle request is unsupported in AsyncMultiInterestUserProcessor!");
     }
 
     /**
diff --git a/src/main/java/com/alipay/remoting/rpc/protocol/AsyncUserProcessor.java b/src/main/java/com/alipay/remoting/rpc/protocol/AsyncUserProcessor.java
index 383a5e54..578c24fc 100644
--- a/src/main/java/com/alipay/remoting/rpc/protocol/AsyncUserProcessor.java
+++ b/src/main/java/com/alipay/remoting/rpc/protocol/AsyncUserProcessor.java
@@ -21,15 +21,15 @@
 
 /**
  * Extends this to process user defined request in ASYNC way.<br>
- * If you want process reqeuest in SYNC way, please extends {@link SyncUserProcessor}.
- * 
+ * If you want process request in SYNC way, please extends {@link SyncUserProcessor}.
+ *
  * @author xiaomin.cxm
  * @version $Id: AsyncUserProcessor.java, v 0.1 May 16, 2016 8:18:03 PM xiaomin.cxm Exp $
  */
 public abstract class AsyncUserProcessor<T> extends AbstractUserProcessor<T> {
     /**
      * unsupported here!
-     * 
+     *
      * @see com.alipay.remoting.rpc.protocol.UserProcessor#handleRequest(com.alipay.remoting.BizContext, java.lang.Object)
      */
     @Override
@@ -49,4 +49,4 @@ public Object handleRequest(BizContext bizCtx, T request) throws Exception {
      */
     @Override
     public abstract String interest();
-}
\ No newline at end of file
+}
diff --git a/src/main/java/com/alipay/remoting/rpc/protocol/SyncMutiInterestUserProcessor.java b/src/main/java/com/alipay/remoting/rpc/protocol/SyncMultiInterestUserProcessor.java
similarity index 84%
rename from src/main/java/com/alipay/remoting/rpc/protocol/SyncMutiInterestUserProcessor.java
rename to src/main/java/com/alipay/remoting/rpc/protocol/SyncMultiInterestUserProcessor.java
index 75153046..2c0fda2a 100644
--- a/src/main/java/com/alipay/remoting/rpc/protocol/SyncMutiInterestUserProcessor.java
+++ b/src/main/java/com/alipay/remoting/rpc/protocol/SyncMultiInterestUserProcessor.java
@@ -23,12 +23,12 @@
 
 /**
  * Extends this to process user defined request in SYNC way.<br>
- * If you want process reqeuest in ASYNC way, please extends {@link AsynMultiInterestUserProcessor}.
+ * If you want process request in ASYNC way, please extends {@link AsyncMultiInterestUserProcessor}.
  *
  * @author muyun.cyt (muyun.cyt@antfin.com)  2018/7/5   11:19 AM
  */
-public abstract class SyncMutiInterestUserProcessor<T> extends
-                                                       AbstractMultiInterestUserProcessor<T> {
+public abstract class SyncMultiInterestUserProcessor<T> extends
+                                                        AbstractMultiInterestUserProcessor<T> {
 
     /**
      * @see com.alipay.remoting.rpc.protocol.UserProcessor#handleRequest(com.alipay.remoting.BizContext, java.lang.Object)
@@ -44,7 +44,7 @@ public abstract class SyncMutiInterestUserProcessor<T> extends
     @Override
     public void handleRequest(BizContext bizCtx, AsyncContext asyncCtx, T request) {
         throw new UnsupportedOperationException(
-            "ASYNC handle request is unsupported in SyncMutiInterestUserProcessor!");
+            "ASYNC handle request is unsupported in SyncMultiInterestUserProcessor!");
     }
 
     /**
diff --git a/src/main/java/com/alipay/remoting/rpc/protocol/SyncUserProcessor.java b/src/main/java/com/alipay/remoting/rpc/protocol/SyncUserProcessor.java
index b32acc93..3c6800c0 100644
--- a/src/main/java/com/alipay/remoting/rpc/protocol/SyncUserProcessor.java
+++ b/src/main/java/com/alipay/remoting/rpc/protocol/SyncUserProcessor.java
@@ -21,8 +21,8 @@
 
 /**
  * Extends this to process user defined request in SYNC way.<br>
- * If you want process reqeuest in ASYNC way, please extends {@link AsyncUserProcessor}.
- * 
+ * If you want process request in ASYNC way, please extends {@link AsyncUserProcessor}.
+ *
  * @author xiaomin.cxm
  * @version $Id: SyncUserProcessor.java, v 0.1 May 19, 2016 2:47:21 PM xiaomin.cxm Exp $
  */
@@ -35,7 +35,7 @@ public abstract class SyncUserProcessor<T> extends AbstractUserProcessor<T> {
 
     /**
      * unsupported here!
-     * 
+     *
      * @see com.alipay.remoting.rpc.protocol.UserProcessor#handleRequest(com.alipay.remoting.BizContext, com.alipay.remoting.AsyncContext, java.lang.Object)
      */
     @Override
diff --git a/src/test/java/com/alipay/remoting/rpc/common/PortScan.java b/src/test/java/com/alipay/remoting/rpc/common/PortScan.java
index bcc93b88..c77d829e 100644
--- a/src/test/java/com/alipay/remoting/rpc/common/PortScan.java
+++ b/src/test/java/com/alipay/remoting/rpc/common/PortScan.java
@@ -38,8 +38,10 @@ static public int select() {
             ioe.printStackTrace();
         } finally {
             try {
-                ss.close();
-                logger.warn("Server socket close status: {}", ss.isClosed());
+                if (ss != null) {
+                    ss.close();
+                    logger.warn("Server socket close status: {}", ss.isClosed());
+                }
             } catch (IOException e) {
             }
         }
diff --git a/src/test/java/com/alipay/remoting/rpc/exception/ExceptionTest.java b/src/test/java/com/alipay/remoting/rpc/exception/ExceptionTest.java
index 27477b2f..c95cf7ca 100644
--- a/src/test/java/com/alipay/remoting/rpc/exception/ExceptionTest.java
+++ b/src/test/java/com/alipay/remoting/rpc/exception/ExceptionTest.java
@@ -44,7 +44,7 @@
 
 /**
  * exception test
- * 
+ *
  * @author xiaomin.cxm
  * @version $Id: ExceptionTest.java, v 0.1 Apr 6, 2016 9:41:53 PM xiaomin.cxm Exp $
  */
@@ -82,7 +82,7 @@ public void stop() {
     public void testSyncNoProcessor() {
         server.registerUserProcessor(new SimpleServerUserProcessor());
         try {
-            client.invokeSync(addr, new String("No processor for String now!"), 3000);
+            client.invokeSync(addr, "No processor for String now!", 3000);
         } catch (Exception e) {
             Assert.assertEquals(InvokeServerException.class, e.getClass());
         }
diff --git a/src/test/java/com/alipay/remoting/rpc/userprocessor/UserProcessorRegisterHelperTest.java b/src/test/java/com/alipay/remoting/rpc/userprocessor/UserProcessorRegisterHelperTest.java
index 34ea5efc..f719f3b2 100644
--- a/src/test/java/com/alipay/remoting/rpc/userprocessor/UserProcessorRegisterHelperTest.java
+++ b/src/test/java/com/alipay/remoting/rpc/userprocessor/UserProcessorRegisterHelperTest.java
@@ -20,17 +20,14 @@
 import java.util.List;
 import java.util.concurrent.ConcurrentHashMap;
 
+import com.alipay.remoting.rpc.protocol.*;
 import org.junit.Assert;
 import org.junit.Before;
 import org.junit.Test;
 
 import com.alipay.remoting.BizContext;
 import com.alipay.remoting.rpc.common.SimpleServerUserProcessor;
-import com.alipay.remoting.rpc.protocol.MultiInterestUserProcessor;
-import com.alipay.remoting.rpc.protocol.SyncMutiInterestUserProcessor;
-import com.alipay.remoting.rpc.protocol.SyncUserProcessor;
-import com.alipay.remoting.rpc.protocol.UserProcessor;
-import com.alipay.remoting.rpc.protocol.UserProcessorRegisterHelper;
+import com.alipay.remoting.rpc.protocol.SyncMultiInterestUserProcessor;
 import com.alipay.remoting.rpc.userprocessor.multiinterestprocessor.SimpleServerMultiInterestUserProcessor;
 
 /**
@@ -85,7 +82,7 @@ public String interest() {
 
     @Test
     public void testInterestEmptyException() {
-        MultiInterestUserProcessor userProcessor = new SyncMutiInterestUserProcessor() {
+        MultiInterestUserProcessor userProcessor = new SyncMultiInterestUserProcessor() {
             @Override
             public Object handleRequest(BizContext bizCtx, Object request) throws Exception {
                 return request;
diff --git a/src/test/java/com/alipay/remoting/rpc/userprocessor/multiinterestprocessor/SimpleClientMultiInterestUserProcessor.java b/src/test/java/com/alipay/remoting/rpc/userprocessor/multiinterestprocessor/SimpleClientMultiInterestUserProcessor.java
index a65cace6..443567a8 100644
--- a/src/test/java/com/alipay/remoting/rpc/userprocessor/multiinterestprocessor/SimpleClientMultiInterestUserProcessor.java
+++ b/src/test/java/com/alipay/remoting/rpc/userprocessor/multiinterestprocessor/SimpleClientMultiInterestUserProcessor.java
@@ -32,14 +32,14 @@
 import com.alipay.remoting.InvokeContext;
 import com.alipay.remoting.NamedThreadFactory;
 import com.alipay.remoting.rpc.common.RequestBody;
-import com.alipay.remoting.rpc.protocol.SyncMutiInterestUserProcessor;
+import com.alipay.remoting.rpc.protocol.SyncMultiInterestUserProcessor;
 
 /**
  * @antuor muyun.cyt (muyun.cyt@antfin.com)  2018/7/5   11:20 AM
  */
 public class SimpleClientMultiInterestUserProcessor
                                                    extends
-                                                   SyncMutiInterestUserProcessor<MultiInterestBaseRequestBody> {
+                                                   SyncMultiInterestUserProcessor<MultiInterestBaseRequestBody> {
     /** logger */
     private static final Logger logger          = LoggerFactory
                                                     .getLogger(SimpleClientMultiInterestUserProcessor.class);
@@ -237,4 +237,4 @@ public List<String> multiInterest() {
         list.add(RequestBodyC2.class.getName());
         return list;
     }
-}
\ No newline at end of file
+}
diff --git a/src/test/java/com/alipay/remoting/rpc/userprocessor/multiinterestprocessor/SimpleServerMultiInterestUserProcessor.java b/src/test/java/com/alipay/remoting/rpc/userprocessor/multiinterestprocessor/SimpleServerMultiInterestUserProcessor.java
index 43fd3706..b9c6b838 100644
--- a/src/test/java/com/alipay/remoting/rpc/userprocessor/multiinterestprocessor/SimpleServerMultiInterestUserProcessor.java
+++ b/src/test/java/com/alipay/remoting/rpc/userprocessor/multiinterestprocessor/SimpleServerMultiInterestUserProcessor.java
@@ -33,14 +33,14 @@
 import com.alipay.remoting.InvokeContext;
 import com.alipay.remoting.NamedThreadFactory;
 import com.alipay.remoting.rpc.common.RequestBody;
-import com.alipay.remoting.rpc.protocol.SyncMutiInterestUserProcessor;
+import com.alipay.remoting.rpc.protocol.SyncMultiInterestUserProcessor;
 
 /**
  * @antuor muyun.cyt (muyun.cyt@antfin.com)  2018/7/5   11:20 AM
  */
 public class SimpleServerMultiInterestUserProcessor
                                                    extends
-                                                   SyncMutiInterestUserProcessor<MultiInterestBaseRequestBody> {
+                                                   SyncMultiInterestUserProcessor<MultiInterestBaseRequestBody> {
 
     /** logger */
     private static final Logger logger          = LoggerFactory