reating a 
 durable <code>TopicSubscriber</code> with the same name and a new topic 
 and/or message 
 selector. Changing a durable subscription is equivalent to unsubscribing 
 (deleting) the old one and creating a new one.

 <P>The <code>unsubscribe</code> method is used to delete a durable 
 subscription. The <code>unsubscribe</code> method can be used at the 
 <code>Session</code> or <code>TopicSession</code> level.
 This method deletes the state being 
 maintained on behalf of the subscriber by its pro