HashMaps... Credits

Hello! I have been working on coding one of my KitPvP plugins with a credit system... In the top i have it so when they first join it adds them to the hash map with hopefully like a "balance" of 0...

Main File:

Code:

package me.ztowne13.zPvP;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.logging.Level;
import java.util.logging.Logger;

import org.bukkit.ChatColor;
import org.bukkit.Location;
import org.bukkit.Material;
import org.bukkit.World;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
import org.bukkit.enchantments.Enchantment;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.entity.PlayerDeathEvent;
import org.bukkit.event.player.PlayerJoinEvent;
import org.bukkit.inventory.ItemStack;
import org.bukkit.inventory.PlayerInventory;
import org.bukkit.inventory.meta.ItemMeta;
import org.bukkit.plugin.PluginDescriptionFile;
import org.bukkit.plugin.java.JavaPlugin;
import org.bukkit.potion.PotionEffect;
import org.bukkit.potion.PotionEffectType;
public class Main extends JavaPlugin{
    public final Logger logger = Logger.getLogger("Minecraft");
    public final Listener pl = new MyPlayerListener();
    public final HashMap<String, Integer> Credits = new HashMap<String, Integer>();
    public void loadConfiguration(){
        saveConfig();
    }

    
    
    

    @Override
    public void onEnable(){
        PluginDescriptionFile pdfFile = this.getDescription();
        this.logger.info(pdfFile.getName() + " " + "Version" + pdfFile.getVersion()  + " " + "has been enabled!");
        getServer().getPluginManager().registerEvents(new MyPlayerListener(), this);
        ArrayList<String> names = new ArrayList<String>();
        getConfig().options().copyDefaults(true);
        saveConfig();
        loadConfiguration();
    }
    
    @Override
    public void onDisable(){
        PluginDescriptionFile pdfFile = this.getDescription();
        this.logger.info(pdfFile.getName() + " " + "Version" + pdfFile.getVersion()  + " " + "has been disabled!");
    }
    //Here For A Reason...
    @EventHandler
     public void onPlayerDeath(PlayerDeathEvent event){
         Player player = event.getEntity().getPlayer();
         Player killer = event.getEntity().getKiller();
         event.setKeepLevel(false);
         event.setDroppedExp(0);
         event.getDrops().clear();
         int balance = Credits.get(player.getName());
          getConfig().set("Credits." + player.getName() + ".Balance", (getConfig().getInt("Credits." + player.getName() + ".Balance") +1));
          killer.sendMessage(ChatColor.RED + "You Gained 1 Credit!");
          saveConfig();
     }
     public void onJoin(PlayerJoinEvent event){
         Player player = event.getPlayer();
         if(Credits.containsKey(event.getPlayer().getDisplayName())){
             player.sendMessage(ChatColor.RED + "Welcome To KitPvP!");
         }else{
             int balance = Credits.get(player.getName());
             Credits.put(event.getPlayer().getDisplayName(), balance);
             player.sendMessage(ChatColor.RED + "Welcome To Your First Time At KitPvP!");
             }
         }

I also have it so when they kill someone it should give them an equivalency of one credit... This is obviously not correct. How can i fix it?
Thanks,
ztowne13

PS: Please don't mark as solved right away... I really like to hear all the responses because sometimes one doesn't work and everyone else thinks its solved. Thankyou SO MUCH!

 

@EventHandler
public void onJoin...
And you should save their credits to a file, or else every reload their credits get reset