Solved Creating a config - NPE

Hi everyone, I am trying to create a config. I've followed both the actual Bukkit documentation, and, examples via the resources sub-section. Unfortunately, I continuously get an NPE. Please point out what I am doing wrong, and hopefully you can help me fix this.

Here is what is in my onEnable:

Code:

 public void onEnable() {
        getServer().getPluginManager().registerEvents(new Listener(), this);
        if (!new File(getDataFolder(), "config.yml").exists()) {
            saveDefaultConfig();
        }
        saveConfig();
}

Here is my Listener class:

Code:

package net.reesenator.tokez.Utils;

import net.reesenator.tokez.Main;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.player.PlayerJoinEvent;

public class Listener implements org.bukkit.event.Listener {
    private Main plugin;

    @EventHandler
    public void onPlayerJoin(PlayerJoinEvent event) {
        Player p = event.getPlayer();
        plugin.getConfig().set("name", "ReeseNator");
        String myName = plugin.getConfig().getString("name");
        p.sendMessage(myName);
        plugin.saveConfig();
    }
}

Here is what I set in the config:

Code:

name: ReeseNator

Here is the stacktrace:

Code:

[20:20:59 ERROR]: Could not pass event PlayerJoinEvent to Tokez v0.1
org.bukkit.event.EventException
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:310) ~[spigot-1.8.8.jar:git-Spigot-db6de12-18fbb24]
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62) ~[spigot-1.8.8.jar:git-Spigot-db6de12-18fbb24]
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:502) [spigot-1.8.8.jar:git-Spigot-db6de12-18fbb24]
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:487) [spigot-1.8.8.jar:git-Spigot-db6de12-18fbb24]
        at net.minecraft.server.v1_8_R3.PlayerList.onPlayerJoin(PlayerList.java:298) [spigot-1.8.8.jar:git-Spigot-db6de12-18fbb24]
        at net.minecraft.server.v1_8_R3.PlayerList.a(PlayerList.java:157) [spigot-1.8.8.jar:git-Spigot-db6de12-18fbb24]
        at net.minecraft.server.v1_8_R3.LoginListener.b(LoginListener.java:144) [spigot-1.8.8.jar:git-Spigot-db6de12-18fbb24]
        at net.minecraft.server.v1_8_R3.LoginListener.c(LoginListener.java:54) [spigot-1.8.8.jar:git-Spigot-db6de12-18fbb24]
        at net.minecraft.server.v1_8_R3.NetworkManager.a(NetworkManager.java:231) [spigot-1.8.8.jar:git-Spigot-db6de12-18fbb24]
        at net.minecraft.server.v1_8_R3.ServerConnection.c(ServerConnection.java:148) [spigot-1.8.8.jar:git-Spigot-db6de12-18fbb24]
        at net.minecraft.server.v1_8_R3.MinecraftServer.B(MinecraftServer.java:814) [spigot-1.8.8.jar:git-Spigot-db6de12-18fbb24]
        at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:374) [spigot-1.8.8.jar:git-Spigot-db6de12-18fbb24]
        at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:654) [spigot-1.8.8.jar:git-Spigot-db6de12-18fbb24]
        at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:557) [spigot-1.8.8.jar:git-Spigot-db6de12-18fbb24]
        at java.lang.Thread.run(Unknown Source) [?:1.8.0_66]
Caused by: java.lang.NullPointerException
        at net.reesenator.Tokez.Utils.Listener.onPlayerJoin(Listener.java:14) ~[?:?]
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[?:1.8.0_66]
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_66]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[?:1.8.0_66]
        at java.lang.reflect.Method.invoke(Unknown Source) ~[?:1.8.0_66]
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:306) ~[spigot-1.8.8.jar:git-Spigot-db6de12-18fbb24]
        ... 14 more

Please help me fix it!

~ Reese

 

Please read this:
https://bukkit.org/threads/how-to-r...ubleshoot-your-own-plugins-by-yourself.32457/

 

I have, I and I'm showing the class with which the line is causing the NPE. I need help fixing it. Sometimes even the most experienced developers need assistance.

Regards.

 

@ReeseNator NPEs are an easy fix. Maybe it'll help if you looked up what causes NPEs

 

I feel like you guys are being just plain rude. I know what an NPE is. But if it'd help for you to actually look at my code, rather than just reading the title and giving the response you did, you could actually help me locate the issue. As you can see, the config isn't missing, and/or the key isn't either. I've look at that already, and I'm here because I'm stuck. Unfortunate that I have to explain that.

Regards.

 

@ReeseNator I did look at your code. Something else is "missing". Now what else do you see that you could be using and may also be null?

 

The only thing from looking at my code that could potentially be null is the string. But I don't see why it would be.

 

Tell me all of the objects you are using in the line that is throwing the error.

 

Ok, from searching for hours now, it seems it's null because I didn't add any code to find the config file. I could be wrong, but that's what it appears to be.

 

Name and ReeseNator.

 

Those are the String objects. You are using another Object on that line.

 

@teej107 would the third be plugin?

 

It is a reference to an Object isn't it? Try debugging by printing out to the console whether objects are null or not.

 

teej, it's not neccessary, please pinpoint the line where it could instantiate the plugin variable.

Code:

public class Listener implements org.bukkit.event.Listener {
   private Main plugin;

    @EventHandler
   public void onPlayerJoin(PlayerJoinEvent event) {
        Player p = event.getPlayer();
        plugin.getConfig().set("name", "ReeseNator");
       String myName = plugin.getConfig().getString("name");
        p.sendMessage(myName);
        plugin.saveConfig();
   }
}

@ReeseNator
1.: You don't own the net.reesenator domain. Use me.reesenator or create a github page.
2.: You don't need to save the config in the onEnable()

 

I didn't say I own the domain? I just used it for my package, as most people do.

 

You can't. It's not your domain. Most people use domains, brcause they have them.

 

Pretty sure you can, what can happen if I use it?

 

Your bukkit plugins can get removed, if someone buys that domain

 

Ah, well I won't be posting it on Bukkit anyways.

 

That's not really a good reason to not do the legal thing.

This is the broken line.

• Plugin can be null
• The config cannot be null.
• The "name" string cannot be null
• "ReeseNator" cannot be null.

This is why @teej107 was trying to walk you through this problem. It is extremely simple.

 

As I said, I'm pretty sure I just need to call the config from the folder, which I didn't do. I'll test it, and let you all know if that fixes it. And, I didn't realize just "net" would be illegal. I've seen it done many times though. But alright.

 

@ReeseNator

It's not "illegal" per se, it just violates convention to use a domain you don't own. For example, my packages always begin with com.mythbusterma because I own the domain mythbusterma.com (there's nothing on the website right now, though).

 

Ah, alright. I'll change it then.

 

You wont have problems immediately, but you can get fined if the owner of the domain notices, that you use it. My favorite one sofar is mr @GoogleMaps package, he uses com.googlemaps, and well, googlemaps.com is owned by, you guessed it, google

 

Ah, although I assume the most suits will be coming from privately owned domains, not large companies such as Google. But then again, anything is possible. :3

 

Back to your real problem, because off-topicing is not really good. You never initialize the plugin variable. Create a constructor with the Main as argument

 

I get an error when I register the events for the class in my main.

 

I don't think u need all that.

This is how saveDefaultConfig() works

Code:

public void saveDefaultConfig() {
        File customConfigFile = null;
        if (customConfigFile == null) customConfigFile = new File(getDataFolder(), "config.yml");
       if (!customConfigFile.exists()) this.saveResource("config.yml", false);
    }

so instead of all your checking, just do saveDefaultConfig();

Your onEnable could just be

Code:

public void onEnable() {
        getServer().getPluginManager().registerEvents(new Listener(), this);
        saveDefaultConfig();
}

You could also have the listener in the main class.

 

But then wouldn't I need to do everything in regards to managing the config in the main class?