Distinguishign QueueSession from TopicSession given JMSSession?

Question

The Question:
          Is there a way to distinguish between a QueueSession and a TopicSession, if one has a JMSSession object? Is there a way to distinguish between a Queue and a Topic if one has a DestinationImpl object?
          Unexpected Behavior #1 That Leads to the Question:
          In pre-existing code I've inherited, I find that a call to TopicSession.createTopicSession() returns a weblogic.jms.client.JMSSession object instead of the expected TopicSession reference (though the value returned from the call is cast to a TopicSession and assigned to a TopicSession reference).
          That TopicSession reference is then passed to a function as a Sesson parameter. The function performs instanceof operations to determine whether it is a QueueSession or a TopicSession. The instanceof operation upon that JMSSession object reference that was thus passed in returns true for BOTH a QueueSession AND a TopicSession.
          Unexpected Behavior #2 That Leads to the Question:
          Similarly, after a JNDI lookup() call on the topic / destination name, a weblogic.jms.common.DestinationImpl object is returned instead of the expected Queue or Topic. Subsequent 'instanceof' checks in the code that check for a Queue versus a Topic similarly BOTH succeed for that returned object. So a similar mechanism is operating there.
          My Ignorant Guesswork:
          I'm speculating that the DestinationImpl class acts as a proxy implementing both the Queue and Topic interfaces, and that the JMSSession class similarly implements both the QueueSession and TopicSession interfaces. This doesn't seem like a good thing to do, since one can no longer distinguish between 'em, but hey, surely someone must've had a reason to do so (or to do something like it).
          FYI:
          I have limited Java experience, and am just now learning to work with EJB and WebLogic, with NO other folks around me who know the language or the framework. Help, insight, and a gentle push in the right direction will be sincerely appreciated.

Answer 1

A-HA! Answering my own question, here, so ignore my topic. I found two old newsgroup archive references to apparently the exact same problem. The following captures the response found there --
          Yes, the weblogic.jms.common.DestinationImpl class implements both javax.jms.Queue and javax.jms.Topic, and yes, this creates a problem distinguishing them. BEA provides a work-around API:
          ((weblogic.jms.common.DestinationImpl)dest).isQueue()
          "The next release will deprecate the work-around
          in favor of an extension interface, which will be very
          similar - something like:
          ((weblogic.jms.extensions.WLDestination)dest).isQueue()