[ISSUE #3196] Check if "requestHeader" is null before "requestHeader.getTopic()"

broker/src/main/java/org/apache/rocketmq/broker/processor/AbstractSendMessageProcessor.java

@@ -257,8 +257,8 @@ public abstract class AbstractSendMessageProcessor extends AsyncNettyRequestProc
                 try {
                     final SendMessageRequestHeader requestHeader = parseRequestHeader(request);
 
-                    String namespace = NamespaceUtil.getNamespaceFromResource(requestHeader.getTopic());
                     if (null != requestHeader) {
+                        String namespace = NamespaceUtil.getNamespaceFromResource(requestHeader.getTopic());
                         context.setNamespace(namespace);
                         context.setProducerGroup(requestHeader.getProducerGroup());
                         context.setTopic(requestHeader.getTopic());

broker/src/main/java/org/apache/rocketmq/broker/processor/SendMessageProcessor.java

@@ -612,6 +612,7 @@ public class SendMessageProcessor extends AbstractSendMessageProcessor implement
         }
     }
 
+    @Override
     public SocketAddress getStoreHost() {
         return storeHost;
     }