JAVA

spigot cancel repeating task

int taskID;
public void startCountdown(){
	taskID = Bukkit.getServer().getScheduler().scheduleSyncRepeatingTask(this,new Countdown(),20L,20L);
}
public void stopCountdown(){
	Bukkit.getServer().getScheduler().cancelTask(taskID);
}
// 20L = 1 Second

spigot repeating task

Bukkit.getScheduler().scheduleSyncRepeatingTask(plugin, new Runnable() {
    @Override
    public void run() {
        Bukkit.broadcastMessage("This message is shown immediately and then repeated every second");
    }
}, 0L, 20L); //0 Tick initial delay, 20 Tick (1 Second) between repeats

spigot repeating task

private HashMap<UUID, Long> map = new HashMap<UUID, Long>();

@EventHandler
public void onJoin(PlayerJoinEvent event) {
    map.put(event.getPlayer().getUniqueID(), Calendar.getInstance().getTime().getTime());
}