code: @Override
  	public void setClientID(String clientID) throws JMSException
      {
      	externalAccessLock.readLock().lock();
      	try
  		{
      		checkNotClosed();
  	        if (StringTools.isEmpty(clientID))
  	            throw new InvalidClientIDException("Empty client ID");
  	        if (this.clientID != null)
  	            throw new IllegalStateException("Client ID is already set"); // [JMS SPEC]
  	        this.clientID = clientID;
  		}
      	finally
      	{
      		externalAccessLock.readLock().unlock();
      	}
      }
docs: /* (non-Javadoc)
  @see javax.jms.Connection#setClientID(java.lang.String)