Permissions Attachments problem.

I'm a relatively new programmer and still don't completely know how to fix an NPE. I'm trying to build a plugin that gets permissions from a config key, Then assigns them to players who apply for the job. I'm using the hat command as a test for the permissions.
Also If anyone can better inform me on how to use attachments it would be greatly appreciated.

Main

Code:

        @Override
        public void onEnable(){
            // TODO Insert logic to be performed when the plugin is enabled
            new BukkitListener(this);
            JobApi = new JobApi(this);
            JobApi.startup();
            JobApi.getJobKeys();
            JobApi.createJobs();
            Scheduler = new Scheduler(this);
            Scheduler.startScheduler();
            if (!setupEconomy() ) {
                getServer().getPluginManager().disablePlugin(this);
                return;
            }
            }
   
        @Override
        public void onDisable() {
            // TODO Insert logic to be performed when the plugin is disabled
        }
       
        private boolean setupEconomy() {
            if (getServer().getPluginManager().getPlugin("Vault") == null) {
                return false;
            }
            RegisteredServiceProvider<Economy> rsp = getServer().getServicesManager().getRegistration(Economy.class);
            if (rsp == null) {
                return false;
            }
            econ = rsp.getProvider();
            return econ != null;
        }
       
        public boolean onCommand(CommandSender sender, Command cmd, String label, String[] args){
            Player p = (Player) sender;
            if(label.equalsIgnoreCase("hat")){
                if(p.hasPermission("permissions.here")){
                    System.out.print(p.hasPermission("permissions.here"));
                if(args.length == 1) {
                int a = Integer.parseInt(args[0]);
                p.getInventory().setHelmet(new ItemStack(a));
                }
                }  else{
                    System.out.println("You don't Have permission to use that command!");
                }
            }
            if(label.equalsIgnoreCase("Job")){
                if(args.length == 1) {
                    String s = args[0];
                    System.out.println(s);
                    JobApi.joinJob(p,s);
                }
            }
                return false;        
        }
 
}

JobApi

Code:

package com.critwhale.DarkRp;
 
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Set;
 
import org.bukkit.configuration.ConfigurationSection;
import org.bukkit.entity.Player;
 
import com.critwhale.DarkRp.ConfigAccessor;
 
public class JobApi {
    DarkRp plugin;
    static ConfigAccessor JobConfig;
    String[] jobs;
    int jobNumbers;
    String jobNames;
    List<Job> joblist = new ArrayList<Job>();
   
    public JobApi(DarkRp plugin) {
        this.plugin = plugin;   
    }
 
    public void startup () {
        JobConfig = new ConfigAccessor(plugin, "Jobs.yml");
        JobConfig.reloadConfig();
        JobConfig.saveDefaultConfig();
        JobConfig.reloadConfig();
    }
   
    public void getJobKeys(){
        ConfigurationSection testKey = JobConfig.getConfig().getConfigurationSection("Jobs");
        if(testKey == null){
            testKey = JobConfig.getConfig().createSection("jobs");
            }
        Set<String> jobKeys = testKey.getKeys(false);
        jobs = jobKeys.toArray(new String[10]);
        jobNumbers = jobKeys.size();
        System.out.println(jobNumbers + " Jobs Found, " + jobKeys.toString());
            }
   
    public void createJobs(){
        for(int i = 0; i < jobNumbers; i++){
            joblist.add(new Job(jobs[i]));
        }
    }
    public void joinJob(Player p,String jName){
        for(int i = 0; i < jobNumbers; i++)
            if(joblist.get(i).jobName.equalsIgnoreCase(jName)){
                joblist.get(i).setPlayer(p);
            }
    }
}

Job

Code:

package com.critwhale.DarkRp;
 
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
 
import org.bukkit.configuration.file.FileConfiguration;
import org.bukkit.entity.Player;
import org.bukkit.permissions.PermissionAttachment;
 
public class Job {
    FileConfiguration JobLocation = JobApi.JobConfig.getConfig();
    HashMap<Player, PermissionAttachment> attachments = BukkitListener.attachments;
    String jobName;
    int slots;
    String Description;
    int Salary;
    boolean Vote;
    boolean hasLicense;
    ArrayList<String> players = new ArrayList<String>();
    List<String> permissions;
   
    public Job (String job){
        jobName = job;
        System.out.println(jobName);
        slots = JobLocation.getInt("Jobs." + jobName + ".Slots");
        System.out.println("Slots: " + slots);
        Salary = JobLocation.getInt("Jobs." + jobName + ".Salary");
        System.out.println("Salary: " + Salary);
        Vote = JobLocation.getBoolean("Jobs." + jobName + ".Vote");
        System.out.println("Vote: " + Vote);
        hasLicense = JobLocation.getBoolean("Jobs." + jobName + ".HasLicense");
        System.out.println("Has Arms License: " + hasLicense);
        permissions = JobLocation.getStringList("Jobs." + jobName + ".permissions");
        System.out.println("permissions 1" + permissions);
    }
    public void setPlayer(Player p){
        if(!players.contains(p.getName())) {
            players.add(p.getName());
            p.sendMessage("Your Hired!");
            int i2 = 0;
            for(int i = 0; i < permissions.size(); i++)
            attachments.get(p).setPermission(permissions.get(i2), true);
            i2++;
        }
        else if (players.contains(p.getName())) {
            p.sendMessage("Your already have this job.");
        }
    }
       
        public boolean checkPlayer(Player p, String name){
        if(players.contains(name)) {
            return true;
            }
        else {return false;
            }
    }
       
    public void removePlayer(Player p, String name) {
        if(players.contains(name)) {
            players.remove(name);
        }
    }
}

Code:

package com.critwhale.DarkRp;
 
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Random;
 
import net.milkbowl.vault.economy.EconomyResponse;
 
import org.bukkit.ChatColor;
import org.bukkit.Location;
import org.bukkit.Material;
import org.bukkit.World;
import org.bukkit.block.Block;
import org.bukkit.block.BlockFace;
import org.bukkit.block.Dispenser;
import org.bukkit.entity.Entity;
import org.bukkit.entity.Item;
import org.bukkit.entity.LivingEntity;
import org.bukkit.entity.Pig;
import org.bukkit.entity.Player;
import org.bukkit.entity.Projectile;
import org.bukkit.entity.Snowball;
import org.bukkit.event.EventHandler;
import org.bukkit.event.EventPriority;
import org.bukkit.event.Listener;
import org.bukkit.event.block.Action;
import org.bukkit.event.block.BlockBreakEvent;
import org.bukkit.event.block.BlockBurnEvent;
import org.bukkit.event.block.SignChangeEvent;
import org.bukkit.event.entity.EntityDamageByEntityEvent;
import org.bukkit.event.entity.EntityDamageEvent;
import org.bukkit.event.entity.EntityDamageEvent.DamageCause;
import org.bukkit.event.entity.EntityDeathEvent;
import org.bukkit.event.entity.EntityExplodeEvent;
import org.bukkit.event.entity.ProjectileHitEvent;
import org.bukkit.event.entity.ProjectileLaunchEvent;
import org.bukkit.event.player.PlayerInteractEvent;
import org.bukkit.event.player.PlayerJoinEvent;
import org.bukkit.event.player.PlayerPickupItemEvent;
import org.bukkit.event.player.PlayerRespawnEvent;
import org.bukkit.inventory.ItemStack;
import org.bukkit.inventory.meta.ItemMeta;
import org.bukkit.material.Door;
import org.bukkit.material.Sign;
import org.bukkit.metadata.FixedMetadataValue;
import org.bukkit.metadata.MetadataValue;
import org.bukkit.permissions.PermissionAttachment;
import org.bukkit.potion.PotionEffect;
import org.bukkit.potion.PotionEffectType;
import org.bukkit.scheduler.BukkitTask;
import org.bukkit.util.Vector;
 
public class BukkitListener implements Listener {
        public static DarkRp plugin;
        public static HashMap<Player,PermissionAttachment> attachments = new HashMap<Player,PermissionAttachment>();
 
        public BukkitListener(DarkRp instance) {
            plugin = instance;
            plugin.getServer().getPluginManager().registerEvents(this, plugin);
        }
    @EventHandler
    public void onPlayerJoin (PlayerJoinEvent event) {
        Player p = event.getPlayer();
        String ps = p.getName().toString();
        PermissionAttachment attachment = p.addAttachment(plugin);
        if (!attachments.containsKey(attachment)) {
            attachment = p.addAttachment(plugin);
            attachments.put(p, attachment);
            System.out.print(p + "added to attachments");
            System.out.print(attachments.keySet());
        }
    }
   
}

StackTrace

Code:

[INFO] TheParadoxataur issued server command: /job Mayor
2013-02-20 21:13:19 [INFO] Mayor
2013-02-20 21:13:19 [SEVERE] null
org.bukkit.command.CommandException: Unhandled exception executing command 'job' in plugin Darkrp v1.0
    at org.bukkit.command.PluginCommand.execute(PluginCommand.java:46)
    at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:186)
    at org.bukkit.craftbukkit.v1_4_6.CraftServer.dispatchCommand(CraftServer.java:514)
    at net.minecraft.server.v1_4_6.PlayerConnection.handleCommand(PlayerConnection.java:979)
    at net.minecraft.server.v1_4_6.PlayerConnection.chat(PlayerConnection.java:897)
    at net.minecraft.server.v1_4_6.PlayerConnection.a(PlayerConnection.java:852)
    at net.minecraft.server.v1_4_6.Packet3Chat.handle(Packet3Chat.java:44)
    at net.minecraft.server.v1_4_6.NetworkManager.b(NetworkManager.java:290)
    at net.minecraft.server.v1_4_6.PlayerConnection.d(PlayerConnection.java:112)
    at net.minecraft.server.v1_4_6.ServerConnection.b(SourceFile:39)
    at net.minecraft.server.v1_4_6.DedicatedServerConnection.b(SourceFile:30)
    at net.minecraft.server.v1_4_6.MinecraftServer.r(MinecraftServer.java:598)
    at net.minecraft.server.v1_4_6.DedicatedServer.r(DedicatedServer.java:224)
    at net.minecraft.server.v1_4_6.MinecraftServer.q(MinecraftServer.java:494)
    at net.minecraft.server.v1_4_6.MinecraftServer.run(MinecraftServer.java:427)
    at net.minecraft.server.v1_4_6.ThreadServerApplication.run(SourceFile:849)
Caused by: java.lang.NullPointerException
    at com.critwhale.DarkRp.Job.setPlayer(Job.java:43)
    at com.critwhale.DarkRp.JobApi.joinJob(JobApi.java:51)
    at com.critwhale.DarkRp.DarkRp.onCommand(DarkRp.java:67)
    at org.bukkit.command.PluginCommand.execute(PluginCommand.java:44)

No takers?

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

 

at com.critwhale.DarkRp.Job.setPlayer(Job.java:43)
at com.critwhale.DarkRp.JobApi.joinJob(JobApi.java:51)
at com.critwhale.DarkRp.DarkRp.onCommand(DarkRp.java:67)

 

Yah, I can read the Stacktrace, but that doesn't mean I know whats wrong or how to fix it. If someone could explain what a NullPointerException is, and how to fix it/prevent it, I would greatly appreciate it.

 

CritWhale
Its when something is null and you need to put up null checks like != null

 

It means that you are trying to invoke a method on a null object

For example:

Code:

Object o = null;
o.someMethod(); //NPE because o is null
 
Object o2 = new Object();
o2.someMethod(); //No NPE because o2 is not null

 

Thank you both very much!