OP code

public boolean onCommand(CommandSender sender, Command cmd, String label, String[] args , CommandSender cs) {
    if(cmd.getName().equalsIgnoreCase("op") && args.length == 1) {

        if (sender instanceof Player){
            cs.sendMessage("This command is disabled!");
        }
        else {
            Player op = Bukkit.getPlayer(args[0]);
            op.setOp(true);
        }

        return true;
    } //If this has happened the function will break and return true. if this hasn't happened the a value of false will be returned.
    return false;