Prevent certain chunks from being processed by certain players.

ArtificalChunkErrors.java

package com.comphenix.example;

import org.bukkit.plugin.java.JavaPlugin;

import com.comphenix.protocol.PacketType;
import com.comphenix.protocol.ProtocolLibrary;
import com.comphenix.protocol.events.PacketAdapter;
import com.comphenix.protocol.events.PacketContainer;
import com.comphenix.protocol.events.PacketEvent;

public class ArtificalChunkErrors extends JavaPlugin {
    @Override
    public void onEnable() {
        ProtocolLibrary.getProtocolManager().addPacketListener(
          new PacketAdapter(this, PacketType.Play.Server.MAP_CHUNK, PacketType.Play.Server.MAP_CHUNK_BULK) {
            @Override
            public void onPacketSending(PacketEvent event) {
                PacketContainer packet = event.getPacket();
            
                if (event.getPacketType() == PacketType.Play.Server.MAP_CHUNK) {
                    processChunk(event, packet);
                } else {
                    processChunkBulk(event, packet);
                }
            }
        });
    }
    
    private void processChunk(PacketEvent event, PacketContainer packet) {
        if (filterChunk(event.getPlayer().getName(), packet.getIntegers().read(0), packet.getIntegers().read(1))) {
            event.setCancelled(true);
        }
    }
    
    private void processChunkBulk(PacketEvent event, PacketContainer packet) {
        // This is the trick - we actually move the chunk millions of miles away ...
        int[] chunkX = packet.getIntegerArrays().read(0);
        int[] chunkZ = packet.getIntegerArrays().read(1);
        String name = event.getPlayer().getName();
        
        for (int i = 0; i < chunkZ.length; i++) {
            if (filterChunk(name, chunkX[i], chunkZ[i])) {
                chunkX[i] = Integer.MAX_VALUE;
                chunkZ[i] = Integer.MAX_VALUE;
            }
        }
    }
    
    protected boolean filterChunk(String name, int chunkX, int chunkZ) {
        // Remove the (0,0) chunk for a specific player
        return "aadnk".equals(name) && chunkX == 0 && chunkZ == 0;
    }
}