Hope this helps you on what you was wanting...
Code://playerhandler public static boolean isPlayerOn(String playerName) { for (int i = 0; i < maxPlayers; i++) { if (playersCurrentlyOn[i] != null) { if (playersCurrentlyOn[i].equalsIgnoreCase(playerName)) return true; } } return false; } //login method if(PlayerHandler.isPlayerOn(playername)) { disconnected = true; return what ever the code is...; }