/**
  * {@inheritDoc}
  *
  * @see org.eclipse.smila.connectivity.queue.worker.internal.AbstractQueueService#stop()
  */
 @Override
 public synchronized void stop() {
   _connectionAccessMap.clear();
   synchronized (_connectionCache) {
     final Iterator<ConnectionWrapper> iterator = _connectionCache.values().iterator();
     while (iterator.hasNext()) {
       final ConnectionWrapper connection = iterator.next();
       try {
         connection.stopInternal();
       } catch (final Throwable e) {
         _log.error(msg("While stopping JMS connection"), e);
       }
       try {
         connection.closeInternal();
       } catch (final Throwable e) {
         _log.error(msg("While closing JMS connection"), e);
       }
       iterator.remove();
     }
   }
   super.stop();
 }