Game.java

  if args.length() == 0 
  {
    player.sendMessage("Incorrect Arguments. Specify gamemode.")
  }else {
    switch(args[0].toLowerCase())
    {
      case "creative":
      case "1":
        player.setGameMode(Gamemode.CREATIVE);
        break;
      case "survival":
      case "0":
        player.setGameMode(GameMode.SURVIVAL);
        break;
      case "adventure":
      case "2":
        player.setGameMode(GameMode.ADVENTURE);
        break;
      case "spectator":
      case "3":
        player.setGameMode(GameMode.SPECTATOR);
        break;
    }
  }