hashmap help?

hi, i'm making a minigame server and i need to make a invincible countdown, but, in different times (when the player joins the arena the player will be invincible for 3 seconds) i know how to create a runnable, i nned a way to decrase all the hashmap integers by 1 at the same time and if the player is with the value 0 the player is removed from the hashmap.

hashmap class:

Code:

package me.thewalkingplay.cookiesplap.arena;

import java.util.HashMap;

import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.entity.Player;

public class ArenaPlayersManager {
   
    static HashMap<String, String> playersInArena = new HashMap<String, String>();
    static HashMap<String, Integer> protectedPlayers = new HashMap<String, Integer>();
   
    @SuppressWarnings("deprecation")
    public static void addPlayerOnArena(String player, String arena) {
       
        playersInArena.put(player, arena);
        Player p = Bukkit.getPlayer(player);
        p.sendMessage(ChatColor.GREEN + "Voce entrou na arena: " + ChatColor.AQUA + arena);
       
    }
   
    public static void removePlayerFromArema(String player) {       
        playersInArena.remove(player);
    }
   
    public static String getPlayerArena(String player) {
        return playersInArena.get(player);
    }
   
    public static boolean playerIsInArena(String player) {
        if (playersInArena.containsKey(player)) {
            return true;
        } else {
            return false;
        }
    }
   
    public static void decraseAllProtectedTime() {
       
       
    }
   
}

sorry for my english, i'm brazilian

 

Too much static.

 

anyone?