Question

I have a asynchronous JMS receiver coded thus (obvious details missing):

connection = connectionFactory.createConnection();
connection.setExceptionListener(new ExceptionListener() {
    @Override
    public void onException(JMSException ex) {
        logger.info("JMS exception " + ex.getMessage());
    }
});

session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
consumer = session.createConsumer(queue);
consumer.setMessageListener(listener);
logger.info("Waiting for a message");
connection.start();

Everything starts up nicely, but when a message arrives I get a JMSException which the ExceptionListener picks up. The exception says:

javax.jms.JMSException: MQJMS2002: failed to get message from MQ queue.
at com.ibm.msg.client.wmq.v6.jms.internal.ConfigEnvironment.newException(ConfigEnvironment.java:374)
at com.ibm.msg.client.wmq.v6.jms.internal.MQMessageConsumer.getMessage(MQMessageConsumer.java:3047)
at com.ibm.msg.client.wmq.v6.jms.internal.MQMessageConsumer.receiveAsync(MQMessageConsumer.java:4042)
at com.ibm.msg.client.wmq.v6.jms.internal.SessionAsyncHelper.run(SessionAsyncHelper.java:507)
at java.lang.Thread.run(Thread.java:662)

The linked exception just says NullPointerException and gives no other details.

I’ve trawled the web looking for an answer but I am no MQ expert and have got nowhere with this. The middleware people here are not very helpful and getting them to do anything is proving slow and painful. I get the impression it’s something to do with queue config but I feel I am clutching at straws.

If anyone has got any suggestions I would be grateful – especially if it is something I can arm myself with and confront middleware 🙂

I’m using the MQ 7.0.0.2 client jars.

Answer 1

Embarrassingly I have just found that a bit of the ‘obvious’ code that I skipped above had a finally block in it that closed the connection shortly after it was opened. Not sure why the error message has to be so vague – telling me that the connection was closed would have saved me hours of head scratching.

Thanks for those that took time to read through my problem!