Join Message Not Working (org.bukkit.event.EventException: null)

"Could not pass event PlayerJoinEvent to JoinMessage v1.1
org.bukkit.event.EventException: null"

...is the first line of the error message I get in the console every time someone logs in to the server.

Since I've only just started with making plugins (this is my second right after a hello world plugin), I've been following tutorials to get the hang of it.

To be specific, this is the tutorial I was following for this plugin:


I followed it letter for letter pretty much. Only changed package and class names, but for some reason I'm getting that error message.

This is my Main:

Code:

package me.skyve.joinmessage;

import me.skyve.joinmessage.join.JoinListener;
import org.bukkit.plugin.java.JavaPlugin;

public class Main extends JavaPlugin {
   
    @Override
    public void onEnable(){
        saveDefaultConfig();
       
        new JoinListener(this);
    }
   
}

This is my JoinListener code:

Code:

package me.skyve.joinmessage.join;

import me.skyve.joinmessage.Main;
import me.skyve.joinmessage.utils.Utils;
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;

public class JoinListener implements Listener {
   
    private static Main plugin;
   
    public JoinListener(Main plugin){
        this.plugin = plugin;
       
        Bukkit.getPluginManager().registerEvents(this, plugin);
    }
   
    @EventHandler
    public void onJoin(PlayerJoinEvent e){
        Player p = e.getPlayer();
       
        if (!p.hasPlayedBefore()){
            Bukkit.broadcastMessage(
                    Utils.chat(plugin.getConfig().getString("firstjoin_message").replace("<player>", p.getName())));
        } else{
            Bukkit.broadcastMessage(
                    Utils.chat(plugin.getConfig().getString("join_message").replace("<player>", p.getName())));
        }
    }
}

This is my Utils code:

Code:

package me.skyve.joinmessage.utils;

import org.bukkit.ChatColor;

public class Utils {

    public static String chat(String s){
        return ChatColor.translateAlternateColorCodes('&', s);
    }
   
}

This is my config.yml file's contents:

Code:

firstJoin_message: '&a<player> &7has joined for the first time!'

join_message '&e<player> &7has joined the game! Welcome back!'

I of course have a plugin.yml file but I didn't think that was necessary to provide.

Does anyone know what I'm doing wrong? Thanks so much for helping.

 

Are you sure that the config contains the join message?
I don't see any code that adds any default values to the config,

 

I'm not exactly sure this was the issue to begin with, but see how in the config file "join_message" has no colon after it, I changed that and now it works somehow. Could this have been the issue? Also sorry I didn't post the full error, I went to do that and then discovered a new error saying that there needed to be the colon and after i fixed that as i said, it worked.

 

Code:

... getString("firstjoin_message") ...

Code:

firstJoin_message: '&a<player> &7has joined for the first time!'

See a slight problem here? firstjoin_message =/= firstJoin_message. Config pathing is case sensitive.

Also, never hang methods off of other methods that are nullable. Also also, this could be compressed down with a simple ternary:

Code:

Bukkit.broadcastMessage(Utils.chat(plugin.getConfig().getString((p.hasPlayedBefore() ? "" : "first") + "join_message").replace("<player>", p.getName())));

However, given the fact getString() is nullable when not passed a value, I wouldn't actually do that. I'd do

Code:

String msg = plugin.getConfig().getString((p.hasPlayedBefore() ? "" : "first") + "join_message");
if (msg == null) return;

Bukkit.broadcastMessage(Utils.chat(msg.replace("<player>", p.getName())));

 

This is really helpful. Thanks so much. I'm really new to all this so I didn't know it was case sensitive. The tutorial I was watching must have fixed this off camera before demonstrating it working. I will keep the suggestions in mind for future projects as well. Again thanks so much.

 

No problem! I recommend sticking to all lowercase when possible, it avoids issues like this. The only time I mix case is in variables and class names, stuff like that. Since end users may edit config files manually, keeping it l/c means less chance they'll bungle it.

Also it's a good idea to keep casing in mind when writing functions. So like when you want to, say, switch on args in a command:

Code:

onCommand {
  switch (cmd.getName().toLowerCase()) {
  case "arg1":
  .. etc

Anything that can be touched by the user could be messed up by said user, so I usually force to lowercase all the time except for when I'm actually writing out (like I'd l/c their input if I need to check something, but if their input is going to be the displayname of an item you certainly don't want to l/c it when writing that for example).