Need help with my own API

This plugin isn't the greatest. I was just using it for testing. I believe I am getting an error everytime my API tries to access its own config. It sends an error once another plugin tries to call the method using my own API.

Here is a picture of the error in the console:
This is the error that I get when I join the server.
http://prntscr.com/jvfhm0

The error involves two plugins:

Joiner Plugin
Simply sends a message to the player once they join.

Code (Text):

package me.markiscool.Joiner;

import org.bukkit.Bukkit;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.player.PlayerJoinEvent;
import org.bukkit.plugin.java.JavaPlugin;

import me.markiscool.MyAPI.JoinerAPI;

public class JoinerMain extends JavaPlugin implements Listener {

    JoinerAPI core = (JoinerAPI) Bukkit.getServer().getPluginManager().getPlugin("MyAPI");
 
    @Override
    public void onEnable() {
        getServer().getPluginManager().registerEvents(this,this);
    }
    @EventHandler
    public void onPlayerJoin(PlayerJoinEvent e) {
        core.welcomeMessage(e.getPlayer());
    }
 
}
 

MyAPI
MyAPI plugin consists of two classes; the main class and the class that holds the method.

MyAPIMain
I don't believe the error is in this class as it is fairly simple, but I'm putting it here anyway.

Code (Text):

package me.markiscool.MyAPI;

import org.bukkit.plugin.java.JavaPlugin;

public class MyAPIMain extends JavaPlugin {
 
    @Override
    public void onEnable() {
        getConfig().options().copyDefaults(true);
        saveConfig();
    }
 

JoinerAPI
The class in the "MyAPI" plugin which contains the methods meant to be used by my "Joiner" plugin.

Code (Text):

package me.markiscool.MyAPI;

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


public class JoinerAPI {

    MyAPIMain plugin = MyAPIMain.getPlugin(MyAPIMain.class);
 
    public void welcomeMessage(Player player) {

        String configMessage = plugin.getConfig().getString("message");
        String splitConfigMessage[] = configMessage.split("*");
        player.sendMessage(ChatColor.translateAlternateColorCodes('&', splitConfigMessage[0] + player.getName() + splitConfigMessage[1]));
     
    }
 
}
 

And lastly, just in case the error is something completely different, here is the default config.

Code (Text):

message: '&bWelcome &e* &bto the server!'
 

This probably has a super easy fix. I'd appreciate any help

 

I changed it up a bit. Like this?

Code (Text):

public class MyAPIMain extends JavaPlugin {
   
    public GameManager m;
   
    @Override
    public void onEnable() {
        m = new GameManager();
    }
}
 

Code (Text):

package me.markiscool.MyAPI;

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

public class GameManager {
    public void sendWelcomeMessage(Player player) {
        player.sendMessage("Welcome to the server, " + ChatColor.YELLOW + player.getName());
    }
}
 

Code (Text):

package me.markiscool.Joiner;

import org.bukkit.Bukkit;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.player.PlayerJoinEvent;
import org.bukkit.plugin.java.JavaPlugin;

import me.markiscool.MyAPI.MyAPIMain;

public class JoinerMain extends JavaPlugin implements Listener {

    private MyAPIMain api = (MyAPIMain) Bukkit.getServer().getPluginManager().getPlugin("MyAPI");

    @Override
    public void onEnable() {
        getServer().getPluginManager().registerEvents(this, this);
    }

    @EventHandler
    public void onPlayerJoin(PlayerJoinEvent e) {
        Player player = e.getPlayer();
        api.m.sendWelcomeMessage(player);
    }

}