Solved 'plugin' variable is null in constructor

Hello,

I have been trying to make a TDM plugin, however, in one of my constructors the plugin variable keeps return null and I do not know why, I do the same thing in all of my other classes and they have no issue.

here is my stacktrace:

Code:

05.01 17:21:57 [Server] INFO Enabling Minigame1 v1.0.0
05.01 17:21:57 [Server] ERROR Error occurred while enabling Minigame1 v1.0.0 (Is it up to date?)
05.01 17:21:57 [Server] INFO java.lang.NullPointerException
05.01 17:21:57 [Server] INFO at org.bukkit.plugin.SimplePluginManager.registerEvents(SimplePluginManager.java:523) ~[spigot46.jar:git-Spigot-21fe707-e1ebe52]
05.01 17:21:57 [Server] INFO at me.Jake_0403.MiniGame1.listeners.UpdateGameSB.<init>(UpdateGameSB.java:23) ~[?:?]
05.01 17:21:57 [Server] INFO at me.Jake_0403.MiniGame1.scoreboards.GameScoreboard.<init>(GameScoreboard.java:26) ~[?:?]
05.01 17:21:57 [Server] INFO at me.Jake_0403.MiniGame1.listeners.ChatFormat.<init>(ChatFormat.java:16) ~[?:?]
05.01 17:21:57 [Server] INFO at me.Jake_0403.MiniGame1.TDM.onEnable(TDM.java:26) ~[?:?]
05.01 17:21:57 [Server] INFO at org.bukkit.plugin.java.JavaPlugin.setEnabled(JavaPlugin.java:321) ~[spigot46.jar:git-Spigot-21fe707-e1ebe52]
05.01 17:21:57 [Server] INFO at org.bukkit.plugin.java.JavaPluginLoader.enablePlugin(JavaPluginLoader.java:340) [spigot46.jar:git-Spigot-21fe707-e1ebe52]
05.01 17:21:57 [Server] INFO at org.bukkit.plugin.SimplePluginManager.enablePlugin(SimplePluginManager.java:405) [spigot46.jar:git-Spigot-21fe707-e1ebe52]
05.01 17:21:57 [Server] INFO at org.bukkit.craftbukkit.v1_8_R3.CraftServer.loadPlugin(CraftServer.java:357) [spigot46.jar:git-Spigot-21fe707-e1ebe52]
05.01 17:21:57 [Server] INFO at org.bukkit.craftbukkit.v1_8_R3.CraftServer.enablePlugins(CraftServer.java:317) [spigot46.jar:git-Spigot-21fe707-e1ebe52]
05.01 17:21:57 [Server] INFO at org.bukkit.craftbukkit.v1_8_R3.CraftServer.reload(CraftServer.java:741) [spigot46.jar:git-Spigot-21fe707-e1ebe52]
05.01 17:21:57 [Server] INFO at org.bukkit.Bukkit.reload(Bukkit.java:535) [spigot46.jar:git-Spigot-21fe707-e1ebe52]
05.01 17:21:57 [Server] INFO at org.bukkit.command.defaults.ReloadCommand.execute(ReloadCommand.java:25) [spigot46.jar:git-Spigot-21fe707-e1ebe52]
05.01 17:21:57 [Server] INFO at org.bukkit.command.SimpleCommandMap.dispatch(SimpleCommandMap.java:141) [spigot46.jar:git-Spigot-21fe707-e1ebe52]
05.01 17:21:57 [Server] INFO at org.bukkit.craftbukkit.v1_8_R3.CraftServer.dispatchCommand(CraftServer.java:641) [spigot46.jar:git-Spigot-21fe707-e1ebe52]
05.01 17:21:57 [Server] INFO at org.bukkit.craftbukkit.v1_8_R3.CraftServer.dispatchServerCommand(CraftServer.java:627) [spigot46.jar:git-Spigot-21fe707-e1ebe52]
05.01 17:21:57 [Server] INFO at net.minecraft.server.v1_8_R3.DedicatedServer.aO(DedicatedServer.java:412) [spigot46.jar:git-Spigot-21fe707-e1ebe52]
05.01 17:21:57 [Server] INFO at net.minecraft.server.v1_8_R3.DedicatedServer.B(DedicatedServer.java:375) [spigot46.jar:git-Spigot-21fe707-e1ebe52]
05.01 17:21:57 [Server] INFO at net.minecraft.server.v1_8_R3.MinecraftServer.A(MinecraftServer.java:654) [spigot46.jar:git-Spigot-21fe707-e1ebe52]
05.01 17:21:57 [Server] INFO at net.minecraft.server.v1_8_R3.MinecraftServer.run(MinecraftServer.java:557) [spigot46.jar:git-Spigot-21fe707-e1ebe52]
05.01 17:21:57 [Server] INFO at java.lang.Thread.run(Thread.java:748) [?:1.8.0_211]

I know there are errors in other classes but those are caused because I reference the UpdateGameSB class (the one throwing the NPE) in those classes.

So I know what and where my problem is but I have no idea how to fix it.

here is my main class, TDM:

Code:

package me.Jake_0403.MiniGame1;

import org.bukkit.Bukkit;
import org.bukkit.plugin.java.JavaPlugin;

import me.Jake_0403.MiniGame1.listeners.ChatFormat;
import me.Jake_0403.MiniGame1.listeners.GameStart;
import me.Jake_0403.MiniGame1.listeners.PlayerJoinAndWait;
import me.Jake_0403.MiniGame1.listeners.UpdateGameSB;
import me.Jake_0403.MiniGame1.listeners.UpdateLobbySB;
import me.Jake_0403.MiniGame1.scoreboards.GameScoreboard;
import me.Jake_0403.MiniGame1.scoreboards.LobbyScoreboard;
import me.Jake_0403.MiniGame1.utils.Utils;

public class TDM extends JavaPlugin {

    public void onEnable() {
        saveDefaultConfig();
        getServer().getMessenger().registerOutgoingPluginChannel(this, "BuneeCord");
        GameStart.gameStarted = false;
        Bukkit.getServer().getWorld("world").setFullTime(0);

        // Commands

        // Listeners
        new ChatFormat(this);
        new GameStart(this);
        new PlayerJoinAndWait(this);
        new UpdateGameSB(this);
        new UpdateLobbySB(this);

        // GUIs

        // Scoreboards
        new GameScoreboard(this);
        new LobbyScoreboard(this);

        // Utils
        new Utils(this);
    }
}

And lastly the class that is throwing the error, UpdateGameSB:

Code:

package me.Jake_0403.MiniGame1.listeners;

import org.bukkit.Bukkit;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.entity.PlayerDeathEvent;
import org.bukkit.scoreboard.Objective;
import org.bukkit.scoreboard.Score;

import me.Jake_0403.MiniGame1.TDM;
import me.Jake_0403.MiniGame1.scoreboards.GameScoreboard;

public class UpdateGameSB implements Listener {

    private TDM plugin;
    public int redKills;
    public int blueKills;
    public int playerKills;

    public UpdateGameSB(TDM plugin) {
        this.plugin = plugin;
        Bukkit.getPluginManager().registerEvents(this, plugin);
    }

I can post the full class if needed.
Any advice is welcome
Thanks!!

 

You are calling the constructor for UpdateGameSB from GameScoreboard apparently.
Show that class (GameScoreBoard).

 

@Kars

Code:

package me.Jake_0403.MiniGame1.scoreboards;

import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.scoreboard.DisplaySlot;
import org.bukkit.scoreboard.NameTagVisibility;
import org.bukkit.scoreboard.Objective;
import org.bukkit.scoreboard.Score;
import org.bukkit.scoreboard.Scoreboard;
import org.bukkit.scoreboard.ScoreboardManager;
import org.bukkit.scoreboard.Team;

import me.Jake_0403.MiniGame1.TDM;
import me.Jake_0403.MiniGame1.listeners.UpdateGameSB;
import me.Jake_0403.MiniGame1.utils.Utils;

public class GameScoreboard {

    private TDM plugin;
    public static Scoreboard gameSB;
    public Team red;
    public Team blue;
  
    Utils utils = new Utils(plugin);
    LobbyScoreboard lobbyScoreboard = new LobbyScoreboard(plugin);
    UpdateGameSB updateGameSB = new UpdateGameSB(plugin);
  
    public GameScoreboard(TDM plugin) {
        this.plugin = plugin;
    }

    public void gameScoreboard() {
  
        ScoreboardManager manager = Bukkit.getScoreboardManager();
        setGameSB(manager.getNewScoreboard());
      
        Objective objective = getGameSB().registerNewObjective("PlayTime!", "");
        objective.setDisplaySlot(DisplaySlot.SIDEBAR);
        objective.setDisplayName(utils.chat("&cTDM"));
      
        setRed(getGameSB().registerNewTeam("Red"));
        red.setDisplayName(ChatColor.RED + "RED");
        red.setAllowFriendlyFire(false);
        red.setCanSeeFriendlyInvisibles(true);
        red.setNameTagVisibility(NameTagVisibility.ALWAYS);
      
        setBlue(getGameSB().registerNewTeam("Blue"));
        blue.setDisplayName(ChatColor.BLUE + "BLUE" + ChatColor.RESET);
        blue.setAllowFriendlyFire(false);
        blue.setCanSeeFriendlyInvisibles(true);
        blue.setNameTagVisibility(NameTagVisibility.ALWAYS);


        Score discordLink = objective.getScore("discord.gg/BfWzRxfr");
        discordLink.setScore(1);
      
        Score blank2 = objective.getScore("");
        blank2.setScore(2);
      
        Score blueTeam = objective.getScore(ChatColor.BLUE + "Blue: " +ChatColor.WHITE + String.valueOf(updateGameSB.getBlueKills()));
        blueTeam.setScore(3);
      
        Score redTeam = objective.getScore(ChatColor.RED + "Red: " +ChatColor.WHITE + String.valueOf(updateGameSB.getRedKills()));
        redTeam.setScore(4);
      
        Score blank5 = objective.getScore("");
        blank5.setScore(5);

        Score playerKill = objective.getScore("Kills: " + String.valueOf(updateGameSB.getPlayerKills()));
        playerKill.setScore(6);
      
        setGameSB(getGameSB());
    }
  
    //SETTERS
    public static void setGameSB(Scoreboard scoreboard) {
        gameSB = scoreboard;
    }

    public void setRed(Team team) {
        this.red = team;
    }
  
    public void setBlue(Team team) {
        this.blue = team;
    }
  
    //GETTERS
    public static Scoreboard getGameSB() {
        return gameSB;
    }

    public Team getRed() {
        return this.red;
    }
  
    public Team getBlue() {
        return this.blue;
    }
}

And also yes, I called the class UpdateGameSB inside of GameScoreboard.

 

@Jake_0403 this is your problem here:

PHP:

Utils utils = new Utils(plugin);
LobbyScoreboard lobbyScoreboard = new LobbyScoreboard(plugin);
UpdateGameSB updateGameSB = new UpdateGameSB(plugin);

You are initiating these at class-level with the variable plugin, which is null.

Initiate these in the constructor instead of at class level.

 

@Kars
So I got it to work! I did it a little differently than you suggested, but I still really appreciated your perspective, it will help me in the future.

When you said that I was calling the constructor from GameScoreboard I decided to move the variables 'redKills' 'blueKills' and 'playerKills' to the GameScoreboard class instead of having them in updateGameSB.

By doing this I don't have to reference any class in order to get those variables.

this is what my classes looked like in the end:

updateGameSB:

Code:

package me.Jake_0403.MiniGame1.listeners;

import org.bukkit.Bukkit;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.entity.PlayerDeathEvent;
import org.bukkit.scoreboard.Objective;
import org.bukkit.scoreboard.Score;

import me.Jake_0403.MiniGame1.TDM;
import me.Jake_0403.MiniGame1.scoreboards.GameScoreboard;

public class UpdateGameSB implements Listener {

    private TDM plugin;
  
    GameScoreboard gameScoreboard = new GameScoreboard(plugin);

    public UpdateGameSB(TDM plugin) {
        this.plugin = plugin;
        Bukkit.getPluginManager().registerEvents(this, plugin);
    }

    @EventHandler
    public void redKill(PlayerDeathEvent e) {
        if (GameStart.gameStarted == true) {
            if (((GameScoreboard) GameScoreboard.getGameSB()).getBlue()
                    .hasEntry(e.getEntity().getPlayer().getName()) == true) {
                gameScoreboard.setRedScore(gameScoreboard.getRedScore() + 1);

                for (Player p : Bukkit.getOnlinePlayers()) {
                    p.setScoreboard(GameScoreboard.getGameSB());
                }
            } else {
                return;
            }
        } else {
            return;
        }
    }

    @EventHandler
    public void blueKill(PlayerDeathEvent e) {
        if (GameStart.gameStarted == true) {
            if (((GameScoreboard) GameScoreboard.getGameSB()).getRed()
                    .hasEntry(e.getEntity().getPlayer().getName()) == true) {
                gameScoreboard.setBlueScore(gameScoreboard.getBlueScore() + 1);

                for (Player p : Bukkit.getOnlinePlayers()) {
                    p.setScoreboard(GameScoreboard.getGameSB());
                }
            } else {
                return;
            }
        } else {
            return;
        }
    }

    @EventHandler
    public void playerKill(PlayerDeathEvent e) {
        Player p = ((Player) e).getPlayer();

        if (p.getKiller() == null) {
            return; //this is temporary
//Use a list to make a collection of all the EntityDamageEvents and then check to see if the DamageEvent.getPlayer == DeathEvent.getPlayer, then check if DamageEvent.getDamgageCause() instanceof Entity, if it is, DeathEvent.getPlayer().getKiller() == DamgeEvent.getDamgeCause().getEntity().getPlayer();
        } else { // (if p.getKiller() != null) {
            Player killer = p.getKiller();

            gameScoreboard.setPlayerScore(killer, gameScoreboard.getPlayerScore() + 1);
            killer.setScoreboard(GameScoreboard.getGameSB());
        }
    }
}

gameScoreboard:

Code:

package me.Jake_0403.MiniGame1.scoreboards;

import org.bukkit.Bukkit;
import org.bukkit.ChatColor;
import org.bukkit.entity.Player;
import org.bukkit.scoreboard.DisplaySlot;
import org.bukkit.scoreboard.NameTagVisibility;
import org.bukkit.scoreboard.Objective;
import org.bukkit.scoreboard.Score;
import org.bukkit.scoreboard.Scoreboard;
import org.bukkit.scoreboard.ScoreboardManager;
import org.bukkit.scoreboard.Team;

import me.Jake_0403.MiniGame1.TDM;
import me.Jake_0403.MiniGame1.utils.Utils;

public class GameScoreboard {

    private TDM plugin;
    public static Scoreboard gameSB;
    public Team red;
    public Team blue;
    public int redScore;
    public int blueScore;
    public int playerScore;
  
    Utils utils = new Utils(plugin);
  
    public GameScoreboard(TDM plugin) {
        this.plugin = plugin;
    }

    public void gameScoreboard() {
  
        ScoreboardManager manager = Bukkit.getScoreboardManager();
        setGameSB(manager.getNewScoreboard());
      
        Objective objective = getGameSB().registerNewObjective("PlayTime!", "");
        objective.setDisplaySlot(DisplaySlot.SIDEBAR);
        objective.setDisplayName(utils.chat("&cTDM"));
      
        setRed(getGameSB().registerNewTeam("Red"));
        red.setDisplayName(ChatColor.RED + "RED");
        red.setAllowFriendlyFire(false);
        red.setCanSeeFriendlyInvisibles(true);
        red.setNameTagVisibility(NameTagVisibility.ALWAYS);
      
        setBlue(getGameSB().registerNewTeam("Blue"));
        blue.setDisplayName(ChatColor.BLUE + "BLUE" + ChatColor.RESET);
        blue.setAllowFriendlyFire(false);
        blue.setCanSeeFriendlyInvisibles(true);
        blue.setNameTagVisibility(NameTagVisibility.ALWAYS);


        Score discordLink = objective.getScore("discord.gg/BfWzRxfr");
        discordLink.setScore(1);
      
        Score blank2 = objective.getScore("");
        blank2.setScore(2);
      
        Score blueTeam = objective.getScore(ChatColor.BLUE + "Blue: " +ChatColor.WHITE + String.valueOf(blueScore));
        blueTeam.setScore(3);
      
        Score redTeam = objective.getScore(ChatColor.RED + "Red: " +ChatColor.WHITE + String.valueOf(redScore));
        redTeam.setScore(4);
      
        Score blank5 = objective.getScore("");
        blank5.setScore(5);

        Score playerKills = objective.getScore("Kills: " + String.valueOf(playerScore));
        playerKills.setScore(6);
      
        setGameSB(getGameSB());
    }
  
    //SETTERS
    public static void setGameSB(Scoreboard scoreboard) {
        gameSB = scoreboard;
    }

    public void setRed(Team team) {
        this.red = team;
    }
  
    public void setBlue(Team team) {
        this.blue = team;
    }
  
    public void setBlueScore(int kills) {
        this.blueScore = kills;
    }
  
    public void setRedScore(int kills) {
        this.redScore = kills;
    }
  
    public void setPlayerScore(Player player, int kills) {
        Objective objective = player.getScoreboard().getObjective("objective");
        Score playerKills = objective.getScore("playerKills");
        kills = Integer.valueOf(playerKills.getEntry());
        this.playerScore = kills;
    }
  
    //GETTERS
    public static Scoreboard getGameSB() {
        return gameSB;
    }

    public Team getRed() {
        return this.red;
    }
  
    public Team getBlue() {
        return this.blue;
    }
  
    public int getBlueScore() {
        return this.blueScore;
    }
  
    public int getRedScore() {
        return this.redScore;
    }
  
    public int getPlayerScore() {
        return playerScore;
    }
}

Thanks for the help!!