Der code

package main.main.listeners;

import org.bukkit.ChatColor;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.player.PlayerBucketEvent;


public class Bucket implements Listener {

    @EventHandler
    public void onJoin(PlayerBucketEvent event) {
        Player player = event.getPlayer();

        player.sendMessage(ChatColor.DARK_RED + "Du hast die Challenge nicht bestanden.");
        player.setHealth(0);




    }



}

ackage main.main.listeners;

import org.bukkit.ChatColor;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.player.PlayerQuitEvent;

public class QuitListener implements Listener {

    @EventHandler
    public void onQuit(PlayerQuitEvent event) {
      Player player = event.getPlayer();
      event.setQuitMessage(ChatColor.BLUE + "Sorry,dass" + player.getName() + "es hier nicht geffallen hat");

    }

}

package main.main.listeners;

import org.bukkit.ChatColor;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.player.PlayerRespawnEvent;


public class Spawn implements Listener {

    @EventHandler
    public void onJoin(PlayerRespawnEvent event) {
        Player player = event.getPlayer();

        player.sendMessage(ChatColor.UNDERLINE + "Auf einen neuen Versuch !");
        player.sendMessage(ChatColor.UNDERLINE + "Warte bitte einen Moment!");




    }



}

package main.main.listeners;

import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.player.PlayerBucketEvent;

public class Testeins implements Listener {

    @EventHandler
    public void onJoin(PlayerBucketEvent event){
        Player player = event.getPlayer();
        player.sendMessage("du hast die Challenge nicht geschaft.");




    }

}

package main.main.listeners;

import org.bukkit.event.Listener;

public class testzwei implements Listener {
}

package main.main;


import main.main.listeners.*;
import org.bukkit.Bukkit;
import org.bukkit.plugin.PluginManager;
import org.bukkit.plugin.java.JavaPlugin;

public final class MAIN extends JavaPlugin {

    private static MAIN instance;



    @Override
    public void onLoad() {
        instance = this;
    }

    @Override
    public void onEnable() {

        PluginManager manager = Bukkit.getPluginManager();
        manager.registerEvents(new Bucket (), this);
        manager.registerEvents( new Spawn (),this);
        manager.registerEvents(new QuitListener(), this);
        manager.registerEvents(new Testeins(),this);
        manager.registerEvents(new testzwei(),this);




    }



        // Plugin startup logi}

    @Override
    public void onDisable() {
        // Plugin shutdown logic
    }

    public static MAIN getInstance() {
        return instance;
    }



}

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>MAIN</groupId>
    <artifactId>MAIN</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>MAIN</name>

    <description>Main</description>
    <properties>
        <java.version>16</java.version>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>${java.version}</source>
                    <target>${java.version}</target>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>3.2.4</version>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <createDependencyReducedPom>false</createDependencyReducedPom>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <filtering>true</filtering>
            </resource>
        </resources>
    </build>

    <repositories>
        <repository>
            <id>spigotmc-repo</id>
            <url>https://hub.spigotmc.org/nexus/content/repositories/snapshots/</url>
        </repository>
        <repository>
            <id>sonatype</id>
            <url>https://oss.sonatype.org/content/groups/public/</url>
        </repository>
    </repositories>

    <dependencies>
        <dependency>
            <groupId>org.spigotmc</groupId>
            <artifactId>spigot-api</artifactId>
            <version>1.15.2-R0.1-SNAPSHOT</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>
</project>