code: private void prefetchFromDestination() throws JMSException
      {
          // Lazy test, do not synchronize here but on response (see addToPrefetchQueue())
      	if (closed)
              return;
  
      	if (traceEnabled)
      		log.trace("#"+id+" Prefetching more from destination "+destination);
      	
      	// Ask for more
          PrefetchQuery query = new PrefetchQuery();
          query.setSessionId(session.getId());
          query.setConsumerId(id);
          transportEndpoint.nonBlockingRequest(query);
      }
docs: Prefetch messages from destination
  @throws JMSException