Example of a self-cancelling Bukkit task.

self-cancelling task example.java

    public void countdown(final Player player){ //A method

        new BukkitRunnable(){ //BukkitRunnable, not Runnable

            int countdown = 10; //Instance variable in our anonymous class to easily hold the countdown value

            @Override
            public void run(){

                if(countdown <= 0 || !player.isOnline()){ //countdown is over or player left the server, just two example reasons to exit

                    this.cancel(); //cancel the repeating task
                    return; //exit the method

                }

                player.sendMessage(ChatColor.RED + "There are " + countdown + " seconds until timtower gets moderator powers."); //Example usage
                countdown--; //decrement

            }
        }.runTaskTimer(plugin, 0, 20); //Repeating task with 0 ticks initial delay, run once per 20 ticks (one second). Make sure you pass a valid instance of your plugin.

    }