CooldownTimers Utility class from SinixPvP

CooldownTimers.java

package com.surgehcf.core.hcf;

import java.util.HashMap;
import java.util.UUID;
import org.bukkit.entity.Player;

public class CooldownTimers
{
  public static void createCooldown(String k)
  {
    if (cooldown.containsKey(k)) {
      throw new IllegalArgumentException("Cooldown already exists.");
    }
    cooldown.put(k, new HashMap());
  }
  
  public static HashMap<UUID, Long> getCooldownMap(String k)
  {
    if (cooldown.containsKey(k)) {
      return cooldown.get(k);
    }
    return null;
  }
  
  public static void addCooldown(String k, Player p, int seconds)
  {
    if (!cooldown.containsKey(k)) {
      throw new IllegalArgumentException(k + " does not exist");
    }
    long next = System.currentTimeMillis() + seconds * 1000L;
    ((HashMap)cooldown.get(k)).put(p.getUniqueId(), Long.valueOf(next));
  }
  
  public static boolean isOnCooldown(String k, Player p)
  {
    return (cooldown.containsKey(k)) && (cooldown.get(k).containsKey(p.getUniqueId())) && (System.currentTimeMillis() <= ((Long)((HashMap)cooldown.get(k)).get(p.getUniqueId())).longValue());
  }
  
  public static int getCooldownForPlayerInt(String k, Player p)
  {
    return (int)((Long) ((HashMap) cooldown.get(k)).get(p.getUniqueId()) - System.currentTimeMillis()) / 1000;
  }
  
  public static long getCooldownForPlayerLong(String k, Player p)
  {
    return (int)(((Long)((HashMap)cooldown.get(k)).get(p.getUniqueId())).longValue() - System.currentTimeMillis());
  }
  
  public static void removeCooldown(String k, Player p)
  {
    if (!cooldown.containsKey(k)) {
      throw new IllegalArgumentException(k + " does not exist");
    }
    ((HashMap)cooldown.get(k)).remove(p.getUniqueId());
  }
  
  private static HashMap<String, HashMap<UUID, Long>> cooldown = new HashMap();
}

An example of unnecessary unboxing would be at line 46, return (int)(((Long)((HashMap)cooldown.get(k)).get(p.getUniqueId())).longValue() - System.currentTimeMillis());

You do not need to get the #longValue() because it already returns a long.

Screenshot from IntelliJ IDEA: