[UNSQUASHABLE] Null Pointer Teleport on Join

Hello Bukkit
I have an unsquashable bug, and have no idea why it is occuring. When a player joins, I want them to teleport to their respective spawns, but every time a player joins, I get this error:

PHP:

2013-11-16 15:35:40 [SEVERE] Could not pass event PlayerTeleportEvent to Multiverse-Core v2.5-b675
org.bukkit.event.EventException
    at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:427)
    at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.java:62)
    at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.java:477)
    at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.java:462)
    at org.bukkit.craftbukkit.v1_6_R3.entity.CraftPlayer.teleport(CraftPlayer.java:382)
    at org.bukkit.craftbukkit.v1_6_R3.entity.CraftEntity.teleport(CraftEntity.java:199)
    at me.ccrama.MineFortress2.Badlands$1.run(Badlands.java:43)
    at org.bukkit.craftbukkit.v1_6_R3.scheduler.CraftTask.run(CraftTask.java:53)
    at org.bukkit.craftbukkit.v1_6_R3.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:345)
    at net.minecraft.server.v1_6_R3.MinecraftServer.t(MinecraftServer.java:524)
    at net.minecraft.server.v1_6_R3.DedicatedServer.t(DedicatedServer.java:227)
    at net.minecraft.server.v1_6_R3.MinecraftServer.s(MinecraftServer.java:488)
    at net.minecraft.server.v1_6_R3.MinecraftServer.run(MinecraftServer.java:421)
    at net.minecraft.server.v1_6_R3.ThreadServerApplication.run(SourceFile:583)
Caused by: java.lang.NullPointerException
    at com.onarandombox.MultiverseCore.listeners.MVPlayerListener.playerTeleport(MVPlayerListener.java:178)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.java:425)
    ... 13 more
2013-11-16 15:35:40 [WARNING] [MineFortress2] Task #21 for MineFortress2 v2.0 generated an exception
java.lang.NullPointerException
    at org.bukkit.craftbukkit.v1_6_R3.entity.CraftPlayer.teleport(CraftPlayer.java:395)
    at org.bukkit.craftbukkit.v1_6_R3.entity.CraftEntity.teleport(CraftEntity.java:199)
    at me.ccrama.MineFortress2.Badlands$1.run(Badlands.java:43)
    at org.bukkit.craftbukkit.v1_6_R3.scheduler.CraftTask.run(CraftTask.java:53)
    at org.bukkit.craftbukkit.v1_6_R3.scheduler.CraftScheduler.mainThreadHeartbeat(CraftScheduler.java:345)
    at net.minecraft.server.v1_6_R3.MinecraftServer.t(MinecraftServer.java:524)
    at net.minecraft.server.v1_6_R3.DedicatedServer.t(DedicatedServer.java:227)
    at net.minecraft.server.v1_6_R3.MinecraftServer.s(MinecraftServer.java:488)
    at net.minecraft.server.v1_6_R3.MinecraftServer.run(MinecraftServer.java:421)
    at net.minecraft.server.v1_6_R3.ThreadServerApplication.run(SourceFile:583)

This is the "badlands.java" mentioned in the stacktrace:

Code:java

package me.ccrama.MineFortress2;
 
 
import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.Location;
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.event.player.PlayerRespawnEvent;
import org.bukkit.plugin.Plugin;
 
import com.shampaggon.crackshot.events.WeaponDamageEntityEvent;
 
public class Badlands implements Listener {
    Location a = new Location(Bukkit.getWorld("arena_badlands"), -336, 81, -182);
    Location b = new Location(Bukkit.getWorld("arena_badlands"), -190, 81, -144);
    Location c = new Location(Bukkit.getWorld("arena_badlands"), -263, 82, -163);
    public void pregameBadlands(){
        if(Lists.getLists().Game.contains("Badlands")){
 
        new Arenahandler().pregame("arena_badlands", a, b, c, "Badlands");
        }
    }
    final Plugin plugin = Bukkit.getPluginManager().getPlugin("MineFortress2");
 
    @EventHandler
    public void Join(PlayerJoinEvent e){
 
        if(Lists.getLists().Game.contains("Badlands")){
 
        if(Bukkit.getOnlinePlayers().length == 2){
            new Arenahandler().startGame(a, b, c);
        }
        final Player player = e.getPlayer();
        Bukkit.getScheduler().scheduleSyncDelayedTask(plugin, new Runnable(){
            public void run(){
        if (Lists.getLists().Blue.contains(player.getName())){
 
 
                      player.teleport(a);   
                        Lists.getLists().Blueplayers.add(player.getName());
 
 
 
 
 
            } else{
 
                          player.teleport(b);   
                          Lists.getLists().Redplayers.add(player.getName());
 
                    }
            }
                }, 3);                   
            }
 
        }
 
    @EventHandler
    public void onDeath(PlayerDeathEvent e){
        if(Lists.getLists().Game.contains("Badlands")){
 
        Player player = (Player) e.getEntity();
        String name = player.getName();
        if(Lists.getLists().Blue.contains(name)){
            Lists.getLists().Blueplayers.remove(name);
        }
        if(Lists.getLists().Red.contains(name)){
            Lists.getLists().Redplayers.remove(name);
        }
        if(Lists.getLists().Redplayers.size() - Lists.getLists().Blueplayers.size() == 0 ){
            Bukkit.broadcastMessage(ChatColor.RED + "RED TEAM HAS WON!");
            new End();
        }
        if(Lists.getLists().Blueplayers.size() - Lists.getLists().Redplayers.size() == 0 ){
            Bukkit.broadcastMessage(ChatColor.BLUE + "BLUE TEAM HAS WON!");
            new End();
        }
        }
    }
    @EventHandler
    public void respawn(PlayerRespawnEvent e){
        if(Lists.getLists().Game.contains("Badlands")){
 
        Player p = e.getPlayer();
        for (Player players : Bukkit.getOnlinePlayers())
        {
            players.hidePlayer
            (p);
 
        }   
        }
    }
    @EventHandler
    public void shot(WeaponDamageEntityEvent e){
        if(Lists.getLists().Game.contains("Badlands")){
 
        if(Lists.getLists().Blueplayers.contains(e.getPlayer().getName() ) || Lists.getLists().Redplayers.contains(e.getPlayer().getName())){
    e.setCancelled(false);
    } else {
        e.setCancelled(true);
    }
        }
    }
}
 

Although it mentions multiverse, I don't believe that is the culprit. Any help is appriciated!

Cheers,
ccrama

 

ccrama
Multiverse handles the multiworld teleports, so I do believe that is the problem.

 

xTrollxDudex, it occurs with other multiworld plugins too though...

 

ccrama
Try using Bukkit.getServer().getWorld(...) instead of just Bukkit.getWorld(...)

 

xTrollxDudex still nothing. Same errors and all.

 

Presumably you are initializing the listener in the onEnable method of your plugin. I think that Bukkit loads worlds after plugins have loaded (not sure about this) so you need to re-initialize the Location variables (a, b, c) after the worlds have loaded.

 

The variables are initiated in the class, which is initiated on join event for the first player. I created the runnable to delay the action, letting the locations load and presumably fix the error. The problem is it works perfectly for my twofort (world) world, but the error occurs on Badlands (arena_badlands) and Doublecross (doublecross) (they implement the same methods, basically the same) They run on non-default worlds, which is probably causing the teleportation errors for my multiworld plugins.

 

Are you able to teleport to the worlds normally through your current multi-world method?

 

Put the initializations of those variables in a constructor and see what happens.

 

Holy crap, thanks so much Garris0n. Is there any particular reason that would have caused the error?

Thanks!

 

After doing a bit of research I'm not sure why that would work at all, they should actually do the same thing. Also, when are you initiating the class, exactly? You said it's in the join event for the first player but an instance of it should be made when you register the event in the first place.

 

ccrama Garris0n
BTW i've had this same problem before, i found that if you reload the server it actually fixes it. (But that would mean reloading the server everytime it starts up which is a pain in the butt)

 

It would help if you read up on instancing Would prevent errors like this from happening in the future http://docs.oracle.com/javase/tutorial/java/javaOO/classvars.html

 

Garris0n,when a player joins, it randomly chooses 1 of 4 classes to initiate. Each of these clasess handel one world's game using a handler class for each gametype (some games have different versions in other worlds). Then when each ends, a new number is chosen and makes a new game. This is a horrible method to use, with lots of problems. Im going to do some research drtshock 's link!

Well the main point I have is that the bug is fixed, but can anyone scour my code to see WHY that fixed it? I am very confused as to why this is happening. Just ask and I'll post some more of my classes!

EDIT by Moderator: merged posts, please use the edit button instead of double posting.

 

Feel free, I'm kinda curious.

 

I suspect that the variables were being initialized before the worlds were actually loaded, causing the error. Waiting to initialize variables until the object is actually instantiated is generally considered to be good practice, I believe.