Cannot fix an NPE [closed]

Question

Error:

Caused by: java.lang.NullPointerException
    at com.mcvigor.RunePlayer.getSkillLevel(RunePlayer.java:90)
    at com.mcvigor.utils.SkillUtils.getChances(SkillUtils.java:12)
    at com.mcvigor.listeners.MiningListener.breakBlocks(MiningListener.java:118)

I'm trying to call SkillUtils.getChances and its resulting in an NPE. I've tried finding the error by reviewing my code and I can't seem to find out why I'm getting the error.

RunePlayer.java:

package com.mcvigor;

import java.util.HashMap;

public class RunePlayer {

    private HashMap<Skills, Integer> skills = new HashMap<Skills, Integer>();
    private HashMap<Skills, Integer> skillXP = new HashMap<Skills, Integer>();
    private String name;

    public RunePlayer(String name) {
        new RunePlayer(name, 1, 1, 3, 10, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0);
    }


    public RunePlayer(String name, int agility, int attack, int combat, int constitution, 
            int construction, int cooking, int crafting, int defence, int dungeoneering,
            int farming, int firemaking, int fishing, int fletching, int herblore, int hunter, int magic, int mining,
            int prayer, int ranged, int runecrafting, int slayer, int smithing, int strength,
            int summoning, int thieving, int woodcutting, int agilityXP, int attackXP, int combatXP, int constitutionXP, 
            int constructionXP, int cookingXP, int craftingXP, int defenceXP, int dungeoneeringXP,
            int farmingXP, int firemakingXP, int fishingXP, int fletchingXP, int herbloreXP, int hunterXP, int magicXP, int miningXP,
            int prayerXP, int rangedXP, int runecraftingXP, int slayerXP, int smithingXP, int strengthXP,
            int summoningXP, int thievingXP, int woodcuttingXP) {
        setName(name);
        skills.put(Skills.AGILITY, agility);
        skills.put(Skills.ATTACK, attack);
        skills.put(Skills.COMBAT, combat);
        skills.put(Skills.CONSTITUTION, constitution);
        skills.put(Skills.CONSTRUCTION, construction);
        skills.put(Skills.COOKING, cooking);
        skills.put(Skills.CRAFTING, crafting);
        skills.put(Skills.DEFENCE, defence);
        skills.put(Skills.DUNGEONEERING, dungeoneering);
        skills.put(Skills.FARMING, farming);
        skills.put(Skills.FIREMAKING, firemaking);
        skills.put(Skills.FISHING, fishing);
        skills.put(Skills.FLETCHING, fletching);
        skills.put(Skills.HERBLORE, herblore);
        skills.put(Skills.HUNTER, hunter);
        skills.put(Skills.MAGIC, magic);
        skills.put(Skills.MINING, mining);
        skills.put(Skills.PRAYER, prayer);
        skills.put(Skills.RANGED, ranged);
        skills.put(Skills.RUNECRAFTING, runecrafting);
        skills.put(Skills.SLAYER, slayer);
        skills.put(Skills.SMITHING, smithing);
        skills.put(Skills.STRENGTH, strength);
        skills.put(Skills.SUMMONING, summoning);
        skills.put(Skills.THIEVING, thieving);
        skills.put(Skills.WOODCUTTING, woodcutting);
        skillXP.put(Skills.AGILITY, agilityXP);
        skillXP.put(Skills.ATTACK, attackXP);
        skillXP.put(Skills.COMBAT, combatXP);
        skillXP.put(Skills.CONSTITUTION, constitutionXP);
        skillXP.put(Skills.CONSTRUCTION, constructionXP);
        skillXP.put(Skills.COOKING, cookingXP);
        skillXP.put(Skills.CRAFTING, craftingXP);
        skillXP.put(Skills.DEFENCE, defenceXP);
        skillXP.put(Skills.DUNGEONEERING, dungeoneeringXP);
        skillXP.put(Skills.FARMING, farmingXP);
        skillXP.put(Skills.FIREMAKING, firemakingXP);
        skillXP.put(Skills.FISHING, fishingXP);
        skillXP.put(Skills.FLETCHING, fletchingXP);
        skillXP.put(Skills.HERBLORE, herbloreXP);
        skillXP.put(Skills.HUNTER, hunterXP);
        skillXP.put(Skills.MAGIC, magicXP);
        skillXP.put(Skills.MINING, miningXP);
        skillXP.put(Skills.PRAYER, prayerXP);
        skillXP.put(Skills.RANGED, rangedXP);
        skillXP.put(Skills.RUNECRAFTING, runecraftingXP);
        skillXP.put(Skills.SLAYER, slayerXP);
        skillXP.put(Skills.SMITHING, smithingXP);
        skillXP.put(Skills.STRENGTH, strengthXP);
        skillXP.put(Skills.SUMMONING, summoningXP);
        skillXP.put(Skills.THIEVING, thievingXP);
        skillXP.put(Skills.WOODCUTTING, woodcuttingXP);

    }


    private void setName(String s) {
        name = s;
    }
    public String getName() {
        return name;
    }

    public int getSkillLevel(Skills skill) {
        return skills.get(skill); // LINE 90 <---------------------
    }

    public void setSkillLevel(Skills skill, int level) {
        skills.put(skill, level);
    }

    public int getSkillXP(Skills skill) {
        return skills.get(skill);
    }

    public void setSkillXP(Skills skill, int level) {
        skills.put(skill, level);
    }

}

SkillUtils.java:

package com.mcvigor.utils;

import com.mcvigor.RuneCraft;
import com.mcvigor.RunePlayer;
import com.mcvigor.Skills;

public class SkillUtils {


    public static int getChances(Skills skill, String player, int levelRequired) {
        RunePlayer rp = RuneCraft.players.get(player);
        int skillLevel = rp.getSkillLevel(skill); // LINE 12 <-------------
        if(skillLevel >= levelRequired) {
            return skillLevel - levelRequired;
        } else {
            return -1;
        }
    }

    public static boolean shouldBreakBlock(int chance, int levelRequired) {
        return chance >= RuneCraft.rand.nextInt((int)(levelRequired * 1.5));
    }
}

MiningListener.java:

package com.mcvigor.listeners;

import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.Material;
import org.bukkit.entity.Player;
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.BlockPlaceEvent;
import org.bukkit.event.player.PlayerInteractEvent;
import org.bukkit.inventory.ItemStack;
import org.bukkit.inventory.PlayerInventory;

import com.mcvigor.RuneCraft;
import com.mcvigor.Skills;
import com.mcvigor.utils.SkillUtils;

public class MiningListener implements Listener {

    RuneCraft plugin;

    public MiningListener(RuneCraft instance) {
        plugin = instance;
    }

    public boolean hasPickaxe(Player p) {
        final PlayerInventory i = p.getInventory();
        if(i.contains(Material.WOOD_PICKAXE) || i.contains(Material.STONE_PICKAXE) || i.contains(Material.GOLD_PICKAXE) || i.contains(Material.IRON_PICKAXE) || i.contains(Material.DIAMOND_PICKAXE)) {
            return true;
        }
        return false;
    }

    public boolean clickedBlockIsMineral(PlayerInteractEvent event) {
        if(event.getClickedBlock() != null && event.getClickedBlock().getType() != null) {  
            Material b = event.getClickedBlock().getType();
            if(b.equals(Material.CLAY) || b.equals(Material.GLOWING_REDSTONE_ORE) || b.equals(Material.REDSTONE_ORE) || b.equals(Material.LAPIS_ORE) || b.equals(Material.IRON_ORE) || b.equals(Material.BEDROCK) || b.equals(Material.COAL_ORE) || b.equals(Material.GOLD_ORE) || b.equals(Material.SPONGE) || b.equals(Material.EMERALD_ORE) || b.equals(Material.DIAMOND_ORE)) {
                return true;
            }
        }
        return false;
    }

    public boolean blockIsMineral(BlockBreakEvent event) {
        if(event.getBlock() != null && event.getBlock().getType() != null) {    
            Material m = event.getBlock().getType();
            if(event.getBlock() != null && m != null || m.equals(Material.CLAY) || m.equals(Material.GLOWING_REDSTONE_ORE) || m.equals(Material.REDSTONE_ORE) || m.equals(Material.LAPIS_ORE) || m.equals(Material.IRON_ORE) || m.equals(Material.BEDROCK) || m.equals(Material.COAL_ORE) || m.equals(Material.GOLD_ORE) || m.equals(Material.SPONGE) || m.equals(Material.EMERALD_ORE) || m.equals(Material.DIAMOND_ORE)) {
                return true;
            }
        }
        return false;
    }

    public boolean hasInventorySpace(Player p) {
        for(ItemStack i : p.getInventory().getContents()) {
            if(i == null || i.getType() == null || i.getType().equals(Material.AIR)) {
                return true;
            }
        }
        return false;
    }

    @EventHandler(ignoreCancelled = true)
    public void placeBlocks(BlockPlaceEvent event) {
        if(event.getPlayer().isOp()) return;
        event.setCancelled(true);
    }

    @EventHandler(priority=EventPriority.MONITOR)
    public void playerRClickOre(final PlayerInteractEvent event) throws InterruptedException { //Ore Interactions

        final Player p = event.getPlayer();

        if(event.getPlayer().isOp() || RuneCraft.busyPlayers.contains(p.getName())) return;

        if(!hasInventorySpace(p) && clickedBlockIsMineral(event) && event.getAction() == Action.LEFT_CLICK_BLOCK) {
            event.setCancelled(true);
            p.sendMessage(ChatColor.GRAY + "You do not have enough space in your inventory to mine this rock.");
        }

        if(clickedBlockIsMineral(event) && event.getAction() == Action.LEFT_CLICK_BLOCK && !hasPickaxe(p) && hasInventorySpace(p)) {
            event.setCancelled(true);
            RuneCraft.busyPlayers.add(p.getName());
            p.sendMessage(ChatColor.GRAY + "You need a " + ChatColor.DARK_RED + "pickaxe " + ChatColor.GRAY + "to mine this rock."); // ADD CHECKS FOR PICKAXE REQUIRED LEVEL TO USE
            RuneCraft.busyPlayers.remove(p.getName());
        }

        if(clickedBlockIsMineral(event) && event.getAction() == Action.RIGHT_CLICK_BLOCK) {

            final String clickedOreTypeNames = event.getClickedBlock().getType().toString().toLowerCase().replaceAll("_", " ").replaceAll("glowing redstone ore", "copper ore").replaceAll("redstone ore", "copper ore").replaceAll("lapis ore", "tin ore").replaceAll("bedrock", "silver ore").replaceAll("sponge", "mithril ore").replaceAll("emerald ore", "adamant ore").replaceAll("diamond ore", "runite ore");

            RuneCraft.busyPlayers.add(p.getName());
            p.sendMessage(ChatColor.GRAY + "You examine the rock for ores...");
            Bukkit.getScheduler().runTaskLater(plugin, new Runnable(){
                public void run() {
                    p.sendMessage(ChatColor.GRAY + "This rock contains " + ChatColor.DARK_RED + clickedOreTypeNames + ChatColor.GRAY + ".");
                    RuneCraft.busyPlayers.remove(p.getName());
                }
            }, 3*20L); // TODO: Change time

        }

    }

    @EventHandler(ignoreCancelled = true, priority=EventPriority.MONITOR)
    public void breakBlocks(final BlockBreakEvent event) { //MINING

        Player p = event.getPlayer();
        final String oreTypeNames = event.getBlock().getType().toString().toLowerCase().replaceAll("_", " ").replaceAll("glowing redstone ore", "copper ore").replaceAll("redstone ore", "copper ore").replaceAll("lapis ore", "tin ore").replaceAll("bedrock", "silver ore").replaceAll("sponge", "mithril ore").replaceAll("emerald ore", "adamant ore").replaceAll("diamond ore", "runite ore");
        final Material originalOre = event.getBlock().getType();

        if(p.isOp() || RuneCraft.busyPlayers.contains(p.getName())) return;

        //RequiredLevels
        int clayChance = (RuneCraft.rand.nextInt(SkillUtils.getChances(Skills.MINING, event.getPlayer().getName(), 1)) + 1);
        int copperChance = (RuneCraft.rand.nextInt(SkillUtils.getChances(Skills.MINING, event.getPlayer().getName(), 1)) + 1);
        int tinChance = (RuneCraft.rand.nextInt(SkillUtils.getChances(Skills.MINING, event.getPlayer().getName(), 1)) + 1);
        int ironChance = (RuneCraft.rand.nextInt(SkillUtils.getChances(Skills.MINING, event.getPlayer().getName(), 15)) + 1);
        int silverChance = (RuneCraft.rand.nextInt(SkillUtils.getChances(Skills.MINING, event.getPlayer().getName(), 20)) + 1);
        int coalChance = (RuneCraft.rand.nextInt(SkillUtils.getChances(Skills.MINING, event.getPlayer().getName(), 30)) + 1);
        int goldChance = (RuneCraft.rand.nextInt(SkillUtils.getChances(Skills.MINING, event.getPlayer().getName(), 40)) + 1);
        int mithrilChance = (RuneCraft.rand.nextInt(SkillUtils.getChances(Skills.MINING, event.getPlayer().getName(), 55)) + 1);
        int adamantChance = (RuneCraft.rand.nextInt(SkillUtils.getChances(Skills.MINING, event.getPlayer().getName(), 70)) + 1);
        int runiteChance = (RuneCraft.rand.nextInt(SkillUtils.getChances(Skills.MINING, event.getPlayer().getName(), 85)) + 1);

        if(!hasPickaxe(p) || !hasInventorySpace(p) || !blockIsMineral(event)) event.setCancelled(true);

        if(hasPickaxe(p) && blockIsMineral(event)) {

            if(!SkillUtils.shouldBreakBlock(clayChance, 1)) {
                event.setCancelled(true);
                p.sendMessage(ChatColor.DARK_RED + "Your mining level is not high enough to mine this rock.");
            }
            event.setCancelled(true);
            p.sendMessage(ChatColor.GRAY + "You swing your pick at the rock.");
            //ADD TIMER WITH PICKAXE TYPE + LEVEL + ORE TYPE MODIFIER HERE
            event.getBlock().setType(Material.COBBLESTONE);
            p.sendMessage(ChatColor.GRAY + "You manage to mine some " + ChatColor.DARK_RED + oreTypeNames + ChatColor.GRAY + ".");  
            event.getBlock().getDrops().clear();
            Bukkit.getScheduler().runTaskLater(plugin, new Runnable(){
                public void run() {
                    event.getBlock().setType(originalOre);
                }
            }, 5*20L); // TODO: Change time

        }

    }

}

Anybody know how to fix this NPE?

Answer 1

Your RunePlayer.getSkillLevel(Skills) Method (and getSkillXP()) should return Integer instead of int.

If your skills HashMap doesn't have the specified skills it returns null. But with the return type of int the autoboxing between int and Integer cannot convert null to int as null is not a valid value for int. Thus you get the NPE.

(edited for readability)