code: public final void rollbackUndelivered( List<String> undeliveredMessageIDs ) throws JMSException
      {
      	externalAccessLock.readLock().lock();
      	try
  		{
  	    	checkNotClosed();
  	        rollbackUpdates(false,true, undeliveredMessageIDs);
  		}
      	finally
      	{
      		externalAccessLock.readLock().unlock();
      	}
      }
docs: Rollback undelivered get operations in this session
  @param undeliveredMessageIDs
  @throws JMSException