会话回滚，回退和死信处理程序

Question

I am using MQQueueSession.rollback() to rollback the unit of work. The message is moved to BACKOUT queue, which is all right.

The question though is how to handle these messages in backout queue? I read that I can use runmqdlq tool but it only works with messages prefixed with MQDLH. Simple MQQueueSession.rollback() doesn't seem to be doing that. What am I doing wrong?

The code sample:

MQQueueConnection connection;
// ...
MQQueueSession session = (MQQueueSession) connection.createQueueSession(true, Session.SESSION_TRANSACTED);
MQQueue queue = (MQQueue) session.createQueue("queue:///TEST");
MQQueueReceiver receiver = (MQQueueReceiver) session.createReceiver(queue);
JMSTextMessage message = null;

try {
    message = (JMSTextMessage) receiver.receive();
    // ...
    session.commit();
} catch (JMSException e) {
    session.rollback();
    e.printStackTrace();
}

Answer 1

A message can be backed out by MQ JMS provider to a back out queue or a dead letter queue for few reasons. Some of them are

1) Badly formatted messages
2) Message not acknowledged by the client application either by doing a Commit in a transacted session or Message.Acknowledge() in a client acknowledged session. In such case a message is redelivered. If the same is delivered again and again, MQ JMS provider moves that message to back out queue based on the BOTHRESH setting on the queue.

The above is called "Poison Message" handling.

Many a times, a queue may not have a back out queue ( BOQUEUE ) defined. In such cases MQ JMS provider moves the poison message to a dead letter queue ( DLQ ) prefixing DLQ header. You can use runmqdlq to handle messages in a DLQ .

Messages in backout queue do not have any header pre-fixed like DLQ . You need to investigate why messages ending up there. Fix the reason(s) and move the message back to original queue so that the message can be delivered to application.