Websphere MQ

Every time I work with MQ and Spring JMS I want to poke my eyes out with a dull instrument. It’s always a pain in the neck. My most recent challenge was trying to get the JMSXUserID field to flow through to the application on the other side of MQ.

First, I created a MessagePostProcessor to add the JMS header

public class MyMessagePostProcessor implements MessagePostProcessor  
{  
	private String userId;

	@Override  
	public Message postProcessMessage(Message msg) throws JMSException  
	{  
		msg.setStringProperty(JmsConstants.JMS_IBM_MQMD_USERIDENTIFIER, userId);  
		msg.setStringProperty("JMSXUserID", userId);  
		return msg;  
	}  
}  

But when I checked the queue with HermesJMS I could see that the JMSXUserID had been overwritten somewhere, so I fired up WireShark and watched for the message and confirmed that the message that was going over the wire already had the JMSXUserID field overwritten. This was a good thing - the issue was in the IBM MQ JMS client code.