Null pointer exception

I am getting a null pointer only if the server reloads, not when players join. The error is occuring on line 166

Code:java

this.getConfig().set(k.getName() + ".kills", kills.get(k.getName()));

Entire Class

Code:java

package me.connor.scoreboard;
 
import java.util.ArrayList;
import java.util.HashMap;
 
import net.milkbowl.vault.economy.Economy;
import net.milkbowl.vault.economy.EconomyResponse;
 
import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
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.plugin.RegisteredServiceProvider;
import org.bukkit.plugin.java.JavaPlugin;
import org.bukkit.scoreboard.DisplaySlot;
import org.bukkit.scoreboard.Objective;
import org.bukkit.scoreboard.Score;
import org.bukkit.scoreboard.Scoreboard;
import org.bukkit.scoreboard.ScoreboardManager;
 
 
public class KD extends JavaPlugin implements Listener {
    public HashMap<String, Scoreboard> UsedScoreboard = new HashMap<String, Scoreboard>();
    public HashMap<String, Integer> kills = new HashMap<String, Integer>();
    public HashMap<String, Integer> deaths = new HashMap<String, Integer>();
    public ArrayList<String> show = new ArrayList<String>();
    public Economy econ = null;
 
 
    public void onEnable() {
        Bukkit.getServer().getPluginManager().registerEvents(this, this);
        this.saveDefaultConfig();
 
        if (!setupEconomy()) {
            getLogger().severe(ChatColor.RED + "Economy disabled due to no Vault dependency found!");
            return;
        }
 
        for(Player p :this.getServer().getOnlinePlayers()) {
            serverReload(p);
        }
    }
 
    public void onDisable() {
        for(Player p : this.getServer().getOnlinePlayers()) {
            this.getConfig().set(p.getName() + ".kills", kills.get(p.getName()));
            this.getConfig().set(p.getName() + ".deaths", deaths.get(p.getName()));
        }
        this.saveDefaultConfig();
    }
 
    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 void serverReload(Player p) {
        getKills(p);
        getDeaths(p);
        setScoreboard(p);
        show.add(p.getName());
    }
 
    public void setScoreboard(Player p) {
        ScoreboardManager manager = Bukkit.getScoreboardManager();
        Scoreboard board = manager.getNewScoreboard();
        //economy enabled from config
        boolean EconomyEnabled = this.getConfig().getBoolean("Economy.enabled");
 
        Objective objective = board.registerNewObjective("score", "dummy");
        objective.setDisplayName(this.getConfig().getString("ScoreboardName"));
        objective.setDisplaySlot(DisplaySlot.SIDEBAR);
 
        Score killsScore = objective.getScore(Bukkit.getOfflinePlayer(ChatColor.BLUE + "Kills:")); //Get a fake offline player
        Score deathsScore = objective.getScore(Bukkit.getOfflinePlayer(ChatColor.RED + "Deaths:")); //Get a fake offline player
 
        killsScore.setScore(kills.get(p.getName()));
        deathsScore.setScore(deaths.get(p.getName()));       
 
        if(EconomyEnabled == true) {
            try{
                Score moneyScore = objective.getScore(Bukkit.getOfflinePlayer(ChatColor.GREEN + "Balance:"));
                moneyScore.setScore((int) getMoney(p));
            } catch(Exception ex) {
                getLogger().severe("Economy disabled due to no Vault dependency found!");
                this.getConfig().set("Economy.enabled", false);
                setScoreboard(p);
            }
        }
 
        p.setScoreboard(board);
    }
 
    public void resetScoreboard(Player p) {
        ScoreboardManager manager = Bukkit.getScoreboardManager();
 
        p.setScoreboard(manager.getNewScoreboard());
    }
 
    public HashMap<String, Integer> getKills(Player p) {
            try {
                kills.put(p.getName(), this.getConfig().getInt(p.getName() + ".kills"));
            }
            catch (Exception ex) {
                kills.put(p.getName(), 0);
                this.getConfig().set(p.getName() + ".kills", kills.get(p.getName()));
                this.saveConfig();
                return kills;
            }
 
        return kills;
    }
 
    public HashMap<String, Integer> getDeaths(final Player p) {
            try { 
                deaths.put(p.getName(), this.getConfig().getInt(p.getName() + ".deaths"));
            }
            catch (Exception ex) {
                deaths.put(p.getName(), 0);
                this.getConfig().set(p.getName() + ".deaths", deaths.get(p.getName()));
                this.saveConfig();
                return deaths;
            }
 
        return deaths;
    }
 
    public double getMoney(Player p) {
        Double money = this.econ.getBalance(p.getName());
        return money;
    }
 
    @EventHandler
    public void onJoin(PlayerJoinEvent e) {
        Player p = e.getPlayer();
        getKills(p);
        getDeaths(p);   
        setScoreboard(p);
        show.add(p.getName());
    }
 
    @EventHandler
    public void onPlayerDeath(PlayerDeathEvent e) {
        Player p = e.getEntity();
 
        if(p.getKiller() instanceof Player){
            Player k = p.getKiller();
 
            int currentKills = kills.get(k.getName());
            currentKills++;
 
            kills.put(k.getName(), currentKills);
 
            this.getConfig().set(k.getName() + ".kills", kills.get(k.getName()));
 
            try {
                double reward = this.getConfig().getDouble("Economy.reward");
                EconomyResponse r = this.econ.depositPlayer(k.getName(), reward);
                if(r.transactionSuccess()) {
                    k.sendMessage(ChatColor.AQUA + "You got $" + reward + " for killing " + p.getName());
                }
            } catch(Exception ex) {
 
            } finally {
 
            if(show.contains(k.getName())) {
                setScoreboard(k);   
            }
            }
        }
 
        int currentDeaths = deaths.get(p.getName());       
        currentDeaths++;
 
        deaths.put(p.getName(), currentDeaths);
 
        setScoreboard(p);
 
        this.getConfig().set(p.getName() + ".deaths", deaths.get(p.getName()));
        this.saveConfig();
    }
 
    public boolean onCommand(CommandSender sender, Command cmd, String commandLabel, String[] args) {
        if(cmd.getName().equalsIgnoreCase("sb")) {
            if(!(sender instanceof Player)) {
                sender.sendMessage(ChatColor.RED + "Only players can use scoreboard!");
                return true;
            }
 
            if(args.length == 0) {
                sender.sendMessage(ChatColor.RED + "Usage: /sb hide/show");
                return true;
            }
 
            //define player
            Player p = (Player) sender;
 
            if(args[0].equalsIgnoreCase("hide")) {
                show.remove(p.getName());
                resetScoreboard(p);
                return true;
            }
 
            if(args[0].equalsIgnoreCase("show")) {
                show.add(p.getName());
                setScoreboard(p);
                return true;
            }
 
        }
 
 
        return true;
    }
}
 

 

That line is in PlayerDeathEvent.. It shouldn't even be called on a reload?

 

RealDope sorry i meant if the server is reloaded and the player was online when it reloaded then they go kill someone or get killed it throws the error.

 

when you reload the maps are cleared. You will need to repopulate them during the oneneble by looping through all players online. Similar to what you have done in the onDisable

 

the_merciless i did that is what the serverReload() method does

 

Try changing your kills and deaths methods to voids, something like this.

Code:

    public void setKills(Player p) {
       
        if (this.getConfig().contains(p.getName() + ".kills")){
            kills.put(p.getName(), this.getConfig().getInt(p.getName() + ".kills"));
        }else{
            kills.put(p.getName(), 0);
            this.getConfig().set(p.getName() + ".kills", 0);
            this.saveConfig();
        }
             
    }
 
    public void setDeaths(final Player p) {
        if (this.getConfig().contains(p.getName() + ".deaths")){
            deaths.put(p.getName(), this.getConfig().getInt(p.getName() + ".deaths"));
        }else{
            deaths.put(p.getName(), 0);
            this.getConfig().set(p.getName() + ".deaths", 0);
            this.saveConfig();
           
        }
    }

 

Nope Didn't work

 

cfil360 Try creating the maps again. So on the serverReload() do kills = new HashMap<>(); first. Null pointers are always very easy to Debug yourself by the way. You could have easily done this by just System.out.println() all the objects that are on that line, that way you can easily see which one is null.

 

Stoux no man it's still not working

 

cfil360 Full stack trace?

 

Stoux here you go

Code:

18:14:17 [SEVERE] Could not pass event PlayerDeathEvent to Scoreboard v1.0
org.bukkit.event.EventException
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.ja
va:427)
        at org.bukkit.plugin.RegisteredListener.callEvent(RegisteredListener.jav
a:62)
        at org.bukkit.plugin.SimplePluginManager.fireEvent(SimplePluginManager.j
ava:477)
        at org.bukkit.plugin.SimplePluginManager.callEvent(SimplePluginManager.j
ava:462)
        at org.bukkit.craftbukkit.v1_6_R3.event.CraftEventFactory.callPlayerDeat
hEvent(CraftEventFactory.java:344)
        at net.minecraft.server.v1_6_R3.EntityPlayer.die(EntityPlayer.java:312)
        at net.minecraft.server.v1_6_R3.EntityLiving.damageEntity(EntityLiving.j
ava:710)
        at net.minecraft.server.v1_6_R3.EntityHuman.damageEntity(EntityHuman.jav
a:714)
        at net.minecraft.server.v1_6_R3.EntityPlayer.damageEntity(EntityPlayer.j
ava:383)
        at net.minecraft.server.v1_6_R3.EntityArrow.l_(EntityArrow.java:229)
        at net.minecraft.server.v1_6_R3.World.entityJoinedWorld(World.java:1354)
 
        at net.minecraft.server.v1_6_R3.World.playerJoinedWorld(World.java:1335)
 
        at net.minecraft.server.v1_6_R3.World.tickEntities(World.java:1223)
        at net.minecraft.server.v1_6_R3.WorldServer.tickEntities(WorldServer.jav
a:480)
        at net.minecraft.server.v1_6_R3.MinecraftServer.t(MinecraftServer.java:5
74)
        at net.minecraft.server.v1_6_R3.DedicatedServer.t(DedicatedServer.java:2
27)
        at net.minecraft.server.v1_6_R3.MinecraftServer.s(MinecraftServer.java:4
88)
        at net.minecraft.server.v1_6_R3.MinecraftServer.run(MinecraftServer.java
:421)
        at net.minecraft.server.v1_6_R3.ThreadServerApplication.run(SourceFile:5
83)
Caused by: java.lang.NullPointerException
        at me.connor.scoreboard.KD.onPlayerDeath(KD.java:187)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at org.bukkit.plugin.java.JavaPluginLoader$1.execute(JavaPluginLoader.ja
va:425)
        ... 18 more
18:14:17 [INFO] cfil360 was shot by Skeleton
>

 

Can you paste your current class as of posting that stack trace? According to that it's line 187, but that couldn't throw an NPE afaik.

 

1Rogue here you go

Code:java

package me.connor.scoreboard;
 
import java.util.ArrayList;
import java.util.HashMap;
 
import net.milkbowl.vault.economy.Economy;
import net.milkbowl.vault.economy.EconomyResponse;
 
import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
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.plugin.RegisteredServiceProvider;
import org.bukkit.plugin.java.JavaPlugin;
import org.bukkit.scoreboard.DisplaySlot;
import org.bukkit.scoreboard.Objective;
import org.bukkit.scoreboard.Score;
import org.bukkit.scoreboard.Scoreboard;
import org.bukkit.scoreboard.ScoreboardManager;
 
 
public class KD extends JavaPlugin implements Listener {
    public HashMap<String, Scoreboard> UsedScoreboard = new HashMap<String, Scoreboard>();
    public HashMap<String, Integer> kills = new HashMap<String, Integer>();
    public HashMap<String, Integer> deaths = new HashMap<String, Integer>();
    public ArrayList<String> show = new ArrayList<String>();
    public Economy econ = null;
 
 
    public void onEnable() {
        Bukkit.getServer().getPluginManager().registerEvents(this, this);
        this.saveDefaultConfig();
 
        if (!setupEconomy()) {
            getLogger().severe(ChatColor.RED + "Economy disabled due to no Vault dependency found!");
            return;
        }
 
        for(Player p : this.getServer().getOnlinePlayers()) {
            serverReload(p);
        }
    }
 
    public void onDisable() {
        for(Player p : this.getServer().getOnlinePlayers()) {
            this.getConfig().set(p.getName() + ".kills", kills.get(p.getName()));
            this.getConfig().set(p.getName() + ".deaths", deaths.get(p.getName()));
        }
        this.saveDefaultConfig();
    }
 
    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 void serverReload(Player p) {
        //recreate hashmaps
        kills = new HashMap<String, Integer>();
        deaths = new HashMap<String, Integer>();
        getKills(p);
        getDeaths(p);
        setScoreboard(p);
        show.add(p.getName());
    }
 
    public void setScoreboard(Player p) {
        ScoreboardManager manager = Bukkit.getScoreboardManager();
        Scoreboard board = manager.getNewScoreboard();
        //economy enabled from config
        boolean EconomyEnabled = this.getConfig().getBoolean("Economy.enabled");
 
        Objective objective = board.registerNewObjective("score", "dummy");
        objective.setDisplayName(this.getConfig().getString("ScoreboardName"));
        objective.setDisplaySlot(DisplaySlot.SIDEBAR);
 
        Score killsScore = objective.getScore(Bukkit.getOfflinePlayer(ChatColor.BLUE + "Kills:")); //Get a fake offline player
        Score deathsScore = objective.getScore(Bukkit.getOfflinePlayer(ChatColor.RED + "Deaths:")); //Get a fake offline player
 
        killsScore.setScore(kills.get(p.getName()));
        deathsScore.setScore(deaths.get(p.getName()));       
 
        if(EconomyEnabled == true) {
            try{
                Score moneyScore = objective.getScore(Bukkit.getOfflinePlayer(ChatColor.GREEN + "Balance:"));
                moneyScore.setScore((int) getMoney(p));
            } catch(Exception ex) {
                getLogger().severe("Economy disabled due to no Vault dependency found!");
                this.getConfig().set("Economy.enabled", false);
                setScoreboard(p);
            }
        }
 
        p.setScoreboard(board);
    }
 
    public void resetScoreboard(Player p) {
        ScoreboardManager manager = Bukkit.getScoreboardManager();
 
        p.setScoreboard(manager.getNewScoreboard());
    }
 
    public void getKills(Player p) {
            try {
                kills.put(p.getName(), this.getConfig().getInt(p.getName() + ".kills"));
            }
            catch (Exception ex) {
                kills.put(p.getName(), 0);
                this.getConfig().set(p.getName() + ".kills", kills.get(p.getName()));
                this.saveConfig();
                return;
            }
 
        return;
    }
 
    public void getDeaths(final Player p) {
            try { 
                deaths.put(p.getName(), this.getConfig().getInt(p.getName() + ".deaths"));
            }
            catch (Exception ex) {
                deaths.put(p.getName(), 0);
                this.getConfig().set(p.getName() + ".deaths", deaths.get(p.getName()));
                this.saveConfig();
                return;
            }
 
        return;
    }
 
    public double getMoney(Player p) {
        Double money = this.econ.getBalance(p.getName());
        return money;
    }
 
    @EventHandler
    public void onJoin(PlayerJoinEvent e) {
        Player p = e.getPlayer();
        getKills(p);
        getDeaths(p);   
        setScoreboard(p);
        show.add(p.getName());
    }
 
    @EventHandler
    public void onPlayerDeath(PlayerDeathEvent e) {
        Player p = e.getEntity();
 
        if(p.getKiller() instanceof Player){
            Player k = p.getKiller();
 
            int currentKills = kills.get(k.getName());
            currentKills++;
 
            kills.put(k.getName(), currentKills);
 
            this.getConfig().set(k.getName() + ".kills", kills.get(k.getName()));
 
            try {
                double reward = this.getConfig().getDouble("Economy.reward");
                EconomyResponse r = this.econ.depositPlayer(k.getName(), reward);
                if(r.transactionSuccess()) {
                    k.sendMessage(ChatColor.AQUA + "You got $" + reward + " for killing " + p.getName());
                }
            } catch(Exception ex) {
 
            } finally {
 
            if(show.contains(k.getName())) {
                setScoreboard(k);   
            }
            }
        }
 
        int currentDeaths = deaths.get(p.getName());       
        currentDeaths++;
 
        deaths.put(p.getName(), currentDeaths);
 
        setScoreboard(p);
 
        this.getConfig().set(p.getName() + ".deaths", deaths.get(p.getName()));
        this.saveConfig();
    }
 
    public boolean onCommand(CommandSender sender, Command cmd, String commandLabel, String[] args) {
        if(cmd.getName().equalsIgnoreCase("sb")) {
            if(!(sender instanceof Player)) {
                sender.sendMessage(ChatColor.RED + "Only players can use scoreboard!");
                return true;
            }
 
            if(args.length == 0) {
                sender.sendMessage(ChatColor.RED + "Usage: /sb hide/show");
                return true;
            }
 
            //define player
            Player p = (Player) sender;
 
            if(args[0].equalsIgnoreCase("hide")) {
                show.remove(p.getName());
                resetScoreboard(p);
                return true;
            }
 
            if(args[0].equalsIgnoreCase("show")) {
                show.add(p.getName());
                setScoreboard(p);
                return true;
            }
 
        }
 
 
        return true;
    }
}
 

 

your map is returning null because it doesn't contain a value for that player on line 187 (ints cannot be null, hence the NPE).

When you reload / start, your .reloadServer() method should be add online players to all the hashmaps, not recreate the hashmaps for every player. Furthermore those maps should be initialized outside the loop otherwise with no players online they will not be initialized.

 

1Rogue i still don't see why the op isn't working then. The catch block should give it a value of 0.

 

Because line 187 essentially does this:

Code:java

int something = null;

which is invalid.

 

Ok but why is the deaths() returning a null value 1Rogue

 

Have you tried turning it off and turning back on?

 

Because you do not add every player to the deaths hashmap on server reloads. You simply recreate the hashmap for every player.

 

1Rogue Dude i am adding every player to the hashmap. Right here in the getDeaths()

Code:java

public void getDeaths(Player p) {
            try { 
                deaths.put(p.getName(), this.getConfig().getInt(p.getName() + ".deaths"));
            }
            catch (Exception ex) {
                deaths.put(p.getName(), 0);
                this.getConfig().set(p.getName() + ".deaths", deaths.get(p.getName()));
                this.saveConfig();
                return;
            }
 
        return;
    }

 

Which is called for every player on reload. However your serverReload method remakes the map every time

 

1Rogue can you please elaborate which part is remaking the map every time

 

Key word in that method being 'try'.

Add some debug messages

public void serverReload(Player p) {
//recreate hashmaps
kills = new HashMap<String, Integer>();
deaths = new HashMap<String, Integer>();

This is the part which creates new maps for each player.

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

 

the_merciless still not working. You don't need to return HashMaps do you?

Edit: doesn't work even when i do.

 

You already initialize the maps outside of the serverReload method, so why are you making new ones every time?

In plain english that method basically says:

"For every online player, delete the previous map, make a new one, and add them".

When you reload, you are removing all previous entries because you recreate the map. Stop doing that.

 

1Rogue i understand that but i was just trying the_merciless suggestion

 

He was only explaining what I've been saying for 3 (4?) posts now.

 

1Rogue Sorry dude im just trying every suggestion because none of them have worked

 

remove these lines from your serverReload method:

Code:java

kills = new HashMap<String, Integer>();
deaths = new HashMap<String, Integer>();

 

1Rogue ok i did that but it still isn't working

Blah1 yes i have tried turning it on and off

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