st.executeUpdate("INSERT INTO gameservers" + "VALUES (null, null, null, "+macAddress+", null)");

CREATE TABLE IF NOT EXISTS `gameservers` (
  `server_id` int(11) NOT NULL default '0',
  `hexid` varchar(50) NOT NULL default '',
  `host` varchar(50) NOT NULL default '',
  `macAddress` varchar(50) NOT NULL default '',
  `firstTime` int(1) NOT NULL default '0',
  PRIMARY KEY  (`server_id`)
) ;

"INSERT INTO gameservers " + "VALUES (null, null, null, '"+macAddress+"', null)"

"VALUES (null, null, null, '"+macAddress+"', null)"