Strange JMSException: Message catalog not found

Question

I have built a module that offers a method to send JMS messages. I am using MQSeries as MOM product.
My send-method uses a QueueConnection created during Instantiation of the class, but creates all other JMS-related objects (like QueueSession, QueueSender, Queue etc.) when called, since these classes are not thread safe according to the IBM docs. I close these resources after usage as recommended.
Now I did some automated testing, i.e. I am sending large amounts auf messages over the queues.
It works perfectly normal at first, but after 103 (usually) or 104 (rarely) sent messages I get a strange exception from a call to my QueueConnection object (outboundConn):
The code:
try {
     outboundSession = outboundConn.createQueueSession(false, Session.AUTO_ACKNOWLEDGE);
} catch (JMSException e) {
     System.out.println("StubConnecion.sendMessage(Message requestMessage, String requestQueueName, boolean synchronous): creating queue connection for sending: "+e);
     Exception lEx = e.getLinkedException();
     System.out.println("Linked exception: "+lEx);
     System.exit(1);
The exception reads:
StubConnecion.sendMessage(Message requestMessage, String requestQueueName, boolean synchronous): creating queue connection for sending: javax.jms.JMSException: MQJMS2005: Fehler beim Erstellen von MQQueueManager f�r 'rtulmx0111:QM_server'
Linked exception: com.ibm.mq.MQException: Message catalog not found
The first line is just my output, the second line is more interesting. It gives a JMS error code with a message. The message is german (as is my version of MQSeries), it translates to: "Error creating MQQueueManager for 'localhost:QM_server'
The JMS Exception encapsulates an IBM-specific MQException.
The reason 2009 means:
"Connection to the queue manager has been lost. This can occur because the queue manager has ended. If the call is an MQGET call with the MQGMO_WAIT option, the wait has been canceled. All connection and object handles are now invalid."
Well, my queue manager has not ended and the listener process one has to start for MQSeries is still running.
Does anybody have an idea what could cause this strange behaviour?

Answer 1

Yes, I DO close the resources after usage. :-)
But I solved, or better worked around the problem.
It only occured when I used MQJMS_TP_CLIENT_MQ_TCPIP as transport type. After correcting the problem that leads to the "unable to load message catalog - mqji" error message whenever one starts a JMS app (it is caused when the mqji properties-files are not in the PATH environment variable), I was able to use MQJMS_TP_BINDINGS_MQ as transport type. That one works great.
Has anyone ever found a place where the differences between the transport types are explained?