Test

int task = 0;
    int counter = 0;

    public void Test() {

        task = Bukkit.getScheduler().scheduleSyncRepeatingTask(this, new Runnable() {

            public void run() {

                counter++;

                if (counter >= 60) {

                    Bukkit.getServer().getScheduler().cancelTask(task);
                } else {

                    for (Player on : Bukkit.getOnlinePlayers()) {

                        Location location = on.getLocation();
                        Block block = location.subtract(0.00, 1.00, 0.00).getBlock();
                        block.setType(Material.AIR);
                        on.sendMessage("§4" + counter);
                    }
                }

            }
        }, 20, 4);

    }

    @EventHandler
    public void counterStart(PlayerDropItemEvent playerdrop) {

        counter = 0;

        this.Test();

    }