/** Destroy the registered JMS Sessions and associated MessageConsumers. */
 @Override
 protected void doShutdown() throws JMSException {
   logger.debug("Closing JMS MessageConsumers");
   for (MessageConsumer consumer : this.consumers) {
     JmsUtils.closeMessageConsumer(consumer);
   }
   logger.debug("Closing JMS Sessions");
   for (Session session : this.sessions) {
     JmsUtils.closeSession(session);
   }
 }