what is my issue

I`ve created a plugin that make cooldown but the cooldown doesn't work.I really need help

Code:

public final class Nothing extends JavaPlugin implements Listener {

    @Override
    public void onEnable() {
        getServer().getPluginManager().registerEvents(this,this);
        // Plugin startup logic

    }
    //Events
    private ArrayList<String> cooldown = new ArrayList<String>();
    public static Nothing plugin = Nothing.plugin;
    @EventHandler
    public void move(PlayerMoveEvent e){
        Player p = e.getPlayer();

        if (p.isSprinting()){
            cooldown.add(p.getName());
            getServer().getScheduler().scheduleSyncDelayedTask(plugin, new Runnable() {

                public void run() {
                    cooldown.remove(p.getName());
            if (Math.random() * 100 < 10) {
                p.sendMessage("1");

            } else if (Math.random() * 100 < 20) {
                p.sendMessage("2");

            } else {
                p.sendMessage("3");

            }
        }
    },20L);

        }
    }
    @Override
    public void onDisable() {
        // Plugin shutdown logic
    }
}

 

sorry i am new in plugins and my question is what runnable can i use instead of this scheduler?

 

thanks alot