// JMSCommunicationThread
 @Override
 protected void closeProducersAndConsumers() throws Exception {
   timeout_timer.cancel();
   server_consumer.close();
   server_consumer = null;
   client_consumer.close();
   client_consumer = null;
   if (client_producer != null) {
     client_producer.close();
     client_producer = null;
   }
 }