Multiple args

    public boolean onCommand(CommandSender sender, Command command, String label, String[] args){
        if (sender instanceof Player) {
            Player player = (Player) sender;

        if (player.hasPermission("ve.gamemode")) {

        if (args.length == 1) {

        if (args[0].equals("0")) {
            player.setGameMode(GameMode.SURVIVAL);
            player.sendMessage(ChatColor.GRAY + "Modified your current gamemode to " + ChatColor.YELLOW + "survival.");
        }
        else if (args[0].equals("1")) {
            player.setGameMode(GameMode.CREATIVE);
            player.sendMessage(ChatColor.GRAY + "Modified your current gamemode to " + ChatColor.YELLOW + "creative.");
        }
        else if (args[0].equals("2")) {
            player.setGameMode(GameMode.ADVENTURE);
            player.sendMessage(ChatColor.GRAY + "Modified your current gamemode to " + ChatColor.YELLOW + "adventure.");
        }
        else if (args[0].equals("3")) {
            player.setGameMode(GameMode.SPECTATOR);
            player.sendMessage(ChatColor.GRAY + "Modified your current gamemode to " + ChatColor.YELLOW + "spectator.");
        }
        }
        else player.sendMessage(ChatColor.RED + "You did not enter the correct arguments.");
        return true;
        }
        else player.sendMessage(ChatColor.RED + "You do not have the right permission.");
        return true;
        }
        else sender.sendMessage(ChatColor.RED + "You cannot execute this command in console.");
        return true;
    }

}