package org.example;

import net.minecraft.core.BlockPos;
import net.minecraft.network.protocol.game.ClientboundLevelChunkWithLightPacket;
import net.minecraft.server.level.ServerChunkCache;
import net.minecraft.server.level.ServerLevel;
import net.minecraft.world.level.block.Blocks;
import net.minecraft.world.level.chunk.LevelChunk;
import org.bukkit.Bukkit;
import org.bukkit.craftbukkit.CraftWorld;
import org.bukkit.craftbukkit.entity.CraftPlayer;
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;

public class Main extends JavaPlugin implements Listener {

    @Override
    public void onEnable() {
        Bukkit.getPluginManager().registerEvents(this, this);
    }

    @EventHandler
    public void onPlayerJoin(PlayerJoinEvent event) {
        Player player = event.getPlayer();
        sendModifiedChunks(player);
    }

    private void sendModifiedChunks(Player player) {
        ServerLevel nmsWorld = ((CraftWorld) player.getWorld()).getHandle();
        ServerChunkCache chunkProvider = nmsWorld.getChunkSource();

        int playerChunkX = player.getLocation().getBlockX() >> 4;
        int playerChunkZ = player.getLocation().getBlockZ() >> 4;

        for (int x = -5; x <= 5; x++) {
            for (int z = -5; z <= 5; z++) {
                LevelChunk chunk = chunkProvider.getChunk(playerChunkX + x, playerChunkZ + z, false);
                if (chunk != null) {
                    // Manipuliere die Blöcke unter Y=-10
                    for (int y = -64; y <= -10; y++) {
                        for (int bx = 0; bx < 16; bx++) {
                            for (int bz = 0; bz < 16; bz++) {
                                BlockPos blockPos = new BlockPos(bx, y, bz);
                                chunk.setBlockState(blockPos, Blocks.AIR.defaultBlockState(), false);
                            }
                        }
                    }
                    ClientboundLevelChunkWithLightPacket packet = new ClientboundLevelChunkWithLightPacket(chunk, nmsWorld.getLightEngine(), null, null, false);
                    ((CraftPlayer) player).getHandle().connection.send(packet);
                }
            }
        }
    }
}



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build.gradle:


plugins {
    id("io.papermc.paperweight.userdev") version "2.0.0-beta.14"
    id("java")
}

group = "org.example"
version = "1.0-SNAPSHOT"

repositories {
    mavenCentral()
}

dependencies {
    testImplementation(platform("org.junit:junit-bom:5.10.0"))
    testImplementation("org.junit.jupiter:junit-jupiter")
    paperweight.paperDevBundle("1.21.4-R0.1-SNAPSHOT")

}

tasks.test {
    useJUnitPlatform()
}