public void setMessageId(String messageId) {
        if (messageId == null) {
            _properties.remove(AMQP_PROP_MESSAGE_ID);
            return;
        }
        
        _properties.put(AMQP_PROP_MESSAGE_ID, messageId);
    }
public void setMessageId ( String messageId ) { if ( messageId == null ) { _properties . remove ( AMQP_PROP_MESSAGE_ID ) ; return ; } _properties . put ( AMQP_PROP_MESSAGE_ID , messageId ) ; }
Sets the value of "messageId" property. If a null value is passed
in, it indicates that the property is not set.

@param  messageId    value of "messageId" property