Resolve same method definition brought by merge

client/src/main/java/org/apache/rocketmq/client/producer/DefaultMQProducer.java

@@ -146,6 +146,15 @@ public class DefaultMQProducer extends ClientConfig implements MQProducer {
         this(null, MixAll.DEFAULT_PRODUCER_GROUP, rpcHook);
     }
 
+    /**
+     * Constructor specifying producer group.
+     *
+     * @param producerGroup Producer group, see the name-sake field.
+     */
+    public DefaultMQProducer(final String producerGroup) {
+        this(null, producerGroup, null);
+    }
+
     /**
      * Constructor specifying producer group.
      *
@@ -228,18 +237,6 @@ public class DefaultMQProducer extends ClientConfig implements MQProducer {
         this(null, producerGroup, null, enableMsgTrace, customizedTraceTopic);
     }
 
-    /**
-     * Constructor specifying producer group, RPC hook, enabled msgTrace flag and customized trace topic name.
-     *
-     * @param producerGroup Producer group, see the name-sake field.
-     * @param rpcHook RPC hook to execute per each remoting command execution.
-     * @param enableMsgTrace Switch flag instance for message trace.
-     * @param customizedTraceTopic The name value of message trace topic.If you don't config,you can use the default trace topic name.
-     */
-    public DefaultMQProducer(final String producerGroup, RPCHook rpcHook, boolean enableMsgTrace,final String customizedTraceTopic) {
-        this(null, producerGroup, rpcHook, enableMsgTrace, customizedTraceTopic);
-    }
-
     /**
      * Constructor specifying namespace, producer group, RPC hook, enabled msgTrace flag and customized trace topic name.
      *