title: MQ message received as byte array instead of String
body: <p>I am using Websphere MQ and reading messages from the queue using Spring integration and a jms adapter.</p>
  
  <p>When I manually add messages to the queue the application is reading them and reading the data as a <code>String</code> and everything is fine.</p>
  
  <p>However, when an external party is adding messages to the queue the application is reading them as a byte array and then throwing this exception:</p>
  
  <pre><code>Caused by: java.lang.ClassCastException: [B cannot be cast to java.lang.String
  </code></pre>
  
  <p>The messages look the same to me in MQExplorer.</p>
  
  <p>Although I have noticed a Format column, where the messages that are being processed as Strings have the value <code>MQSTR</code> and the message being processed as a Byte[] has nothing in there. Could this be related? If so any ideas how to set the "format" of the message?</p>
  
  <p>Does anybody know what determines the payload content type of a message, that way I may be able to recreate the issue at least?</p>