Merge pull request #2058 from RealBar/fix/issue2055

[ISSUE #2055] Fix NPE in SendMessageProcessor.handleRetryAndDLQ

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

@@ -178,7 +178,10 @@ public class SendMessageProcessor extends AbstractSendMessageProcessor implement
 
         int maxReconsumeTimes = subscriptionGroupConfig.getRetryMaxTimes();
         if (request.getVersion() >= MQVersion.Version.V3_4_9.ordinal()) {
-            maxReconsumeTimes = requestHeader.getMaxReconsumeTimes();
+            Integer times = requestHeader.getMaxReconsumeTimes();
+            if (times != null) {
+                maxReconsumeTimes = times;
+            }
         }
 
         if (msgExt.getReconsumeTimes() >= maxReconsumeTimes