Solved Name Cannot Be Null Error

Hi, I've had this problem for a while now and I have no clue how to fix it. So what I'm doing is I'm trying to spawn a wolf on a player's location using wolf.class . However when I run the plugin my console throws me an error saying "Name cannot be null". Can someone HELP me fix this, and by help I mean not giving me the code, but actually walking me through my mistakes so I don't make them again. Thank you

Here's my code:
Pets Class:

Code:

public class Pets extends JavaPlugin{
    String playerName;
    Player player = Bukkit.getPlayerExact(playerName);
    Location loc = player.getLocation();
 
    public void spawnWolf(){
        Wolf wolf = loc.getWorld().spawn(loc, Wolf.class);
       
    }

Main Class:

Code:

public class Core extends JavaPlugin {
 
    Pets pet = new Pets();
 
    @Override
    public void onEnable() {
 
 
    }
 
    @Override
    public void onDisable() {
 
 
    }
 
    @Override
    public boolean onCommand(CommandSender sender, Command cmd, String label, String[] args) {
        if(sender.hasPermission("girithiumpets.wolf")){
            if(cmd.getLabel().equalsIgnoreCase("spawnwolf")){
                pet.spawnWolf();
 
            }
 
        }
 
 
        return false;
    }

Error log:

Code:

org.bukkit.plugin.InvalidPluginException: java.lang.IllegalArgumentException: Name cannot be null
    at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:182)
    at org.bukkit.plugin.SimplePluginManager.loadPlugin(SimplePluginManager.java:305)
    at org.bukkit.plugin.SimplePluginManager.loadPlugins(SimplePluginManager.java:230)
    at org.bukkit.craftbukkit.v1_6_R3.CraftServer.loadPlugins(CraftServer.java:241)
    at org.bukkit.craftbukkit.v1_6_R3.CraftServer.reload(CraftServer.java:613)
    at org.bukkit.Bukkit.reload(Bukkit.java:277)
    at org.bukkit.command.defaults.ReloadCommand.execute(ReloadCommand.java:23)
    at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:192)
    at org.bukkit.craftbukkit.v1_6_R3.CraftServer.dispatchCommand(CraftServer.java:528)
    at org.bukkit.craftbukkit.v1_6_R3.CraftServer.dispatchServerCommand(CraftServer.java:515)
    at net.minecraft.server.v1_6_R3.DedicatedServer.as(DedicatedServer.java:263)
    at net.minecraft.server.v1_6_R3.DedicatedServer.t(DedicatedServer.java:228)
    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.IllegalArgumentException: Name cannot be null
    at org.apache.commons.lang.Validate.notNull(Validate.java:203)
    at org.bukkit.craftbukkit.v1_6_R3.CraftServer.getPlayerExact(CraftServer.java:346)
    at org.bukkit.Bukkit.getPlayerExact(Bukkit.java:417)
    at me.JulesLabador.GirithiumPets.Pets.<init>(Pets.java:20)
    at me.JulesLabador.GirithiumPets.Core.<init>(Core.java:18)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
    at org.bukkit.plugin.java.JavaPluginLoader.loadPlugin(JavaPluginLoader.java:178)
    ... 14 more

 

Code:java

 
    String playerName;
    Player player = Bukkit.getPlayerExact(playerName);

This code is in the class body and so runs before any constructor. How could playerName ever not be null?

 

DefaultSyntax
Are these 2 seperate plugins? If not, why are you extending JavaPlugin to 2 different classes? Only your main class should be extending JavaPlugin, failure to do so may cause "Problems"

 

artish1 It's all from one plugin, just from 2 different classes. I removed the "extends JavaPlugin" part and it still gave me the same error.

_LB

Code:java

    String playerName = "";
    Player player = Bukkit.getPlayerExact(playerName);
    Location loc = player.getLocation();

I gave playerName a value, now it's giving me a NullPointerException error. I want to get the Player's name and location outside of the method so it's not repetitive. If I wanted to do this, what would you recommend doing so that I get the information I need, because in order to do the "Bukkit.getPlayer() method, I'm going to need a String for it.

 

Put the code in the constructor.

 

DefaultSyntax
Why do you never declare the String playerName? I do not see ANYWHERE that you have changed playerName to an actual name besides ""; (and that is null?), atleast create a Constructor with a 'String ownerName' Parameter (or however you want to name it), and then declare that playerName = ownerName; inside the constructor.

 

Null is null, the absence of value. "" is an empty String, not null.

 

Skye
But Bukkit.getPlayerExact(""); will always return null because there is no player named "".

 

Thank you guys so much! I was able to figure out the problem!