Merge pull request #231 from ersaxenas/bug-fix-null-pointer-during-ack

Adding null check for error code

Author: ziyanli-amazon

src/main/java/com/amazon/sqs/javamessaging/AmazonSQSMessagingClientWrapper.java

@@ -377,7 +377,7 @@ private JMSException handleException(SdkException e, String operationName) {
     }
 
     private static String errorCode(AwsServiceException e) {
-        return e.awsErrorDetails() != null ? e.awsErrorDetails().errorCode() : "";
+        return e.awsErrorDetails() != null && e.awsErrorDetails().errorCode() != null ? e.awsErrorDetails().errorCode() : "";
     }