GameMode

@Override
    public boolean onCommand(CommandSender sender,Command cmd,String label,String args[]){

        if(label.equalsIgnoreCase("gm")){
            if(args.length == 1){
                String gm = args[0];
                Player player = (Player)sender;
                switch(gm){
                case "0":
                    player.setGameMode(GameMode.SURVIVAL);

                    break;
                case "1":
                    player.setGameMode(GameMode.CREATIVE);
                    break;
                case "2":
                    player.setGameMode(GameMode.ADVENTURE);
                    break;
                case "3":
                    player.setGameMode(GameMode.SPECTATOR);
                    break;
                }
                return true;
            }
        }

        return false;
    }