Scoreboard Fehler!!!?

[Calib0ur]

Hey,
Mein Fehler ist der
"void is an invalid type for the variable onJoin"???
Hier mein Code

package me.cubeyhd.scoreboard;

import java.util.Calendar;

import org.bukkit.Bukkit;
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.player.PlayerJoinEvent;
import org.bukkit.plugin.java.JavaPlugin;
import org.bukkit.potion.PotionEffect;
import org.bukkit.potion.PotionEffectType;
import org.bukkit.scoreboard.DisplaySlot;
import org.bukkit.scoreboard.Objective;
import org.bukkit.scoreboard.Scoreboard;

public class scoreboard extends JavaPlugin implements Listener {
	public void onEnable() {
		
		getServer().getPluginManager().registerEvents(this, this);
		
		System.out.println("[Scoreboard]Plugin gestartet");
	}
	public void onDisable() {
			System.out.println("[Scoreboard]Plugin gestoppt");
		}
		public boolean onCommand(CommandSender sender, Command cmd, String cmdLabel, String[] args) {
			
			Player p = (Player)sender;
			if (cmd.getName().equalsIgnoreCase("bier")) {
				if(p.hasPermission("bier.bier")) {
					if (args.length == 0) {
					  p.sendMessage("§a§Guten Durst");
					  p.addPotionEffect(new PotionEffect(PotionEffectType.JUMP,400,1));
					  p.addPotionEffect(new PotionEffect(PotionEffectType.SPEED,400,2));
					  p.addPotionEffect(new PotionEffect(PotionEffectType.CONFUSION,440,2)); 
					}
	@EventHandler
	public void onJoin(PlayerJoinEvent e) {        //Fehler
		Scoreboard board = Bukkit.getScoreboardManager().getNewScoreboard();
		Objective obj = board.getObjective("Datum");
		if (obj == null) {
			obj = board.registerNewObjective("Datum","dummy");
		}
		obj.setDisplaySlot(DisplaySlot.SIDEBAR);
		obj.setDisplayName("§6Dates");
		
		Calendar cal = Calendar.getInstance();
		obj.getScore(Bukkit.getOfflinePlayer("§2Jahr")).setScore(cal.get(Calendar.YEAR));
		obj.getScore(Bukkit.getOfflinePlayer("§2Monat")).setScore(cal.get(Calendar.MONTH));
		obj.getScore(Bukkit.getOfflinePlayer("§2Tag")).setScore(cal.get(Calendar.DAY_OF_MONTH));
		
		e.getPlayer().setScoreboard(board);
	}
				}
	return true;
	} else{
	return false;
}
}
}

Hoffe ihr könnt mir hefen

 

[MiCrJonas]

Eine Methode mit void gibt nichts zurück. Also mach das "return false" und "return true" weg!