Detect when fireworks explode.

DetectFireworks.java

package com.comphenix.example;

import org.bukkit.World;
import org.bukkit.entity.Firework;
import org.bukkit.event.Listener;
import org.bukkit.plugin.java.JavaPlugin;

import com.comphenix.protocol.Packets;
import com.comphenix.protocol.ProtocolLibrary;
import com.comphenix.protocol.events.ConnectionSide;
import com.comphenix.protocol.events.PacketAdapter;
import com.comphenix.protocol.events.PacketContainer;
import com.comphenix.protocol.events.PacketEvent;

public class DetectFireworks extends JavaPlugin implements Listener {
    @Override
	public void onEnable() {
		ProtocolLibrary.getProtocolManager().addPacketListener(
		  new PacketAdapter(this, ConnectionSide.SERVER_SIDE, Packets.Server.ENTITY_STATUS) {
			@Override
			public void onPacketSending(PacketEvent event) {
				PacketContainer packet = event.getPacket();
				byte status = packet.getBytes().read(0);
				
				if (status == 17) {
					World world = event.getPlayer().getWorld();
					Firework firework = (Firework) event.getPacket().getEntityModifier(world).read(0);
					
					System.out.println(firework + " just exploded.");
				}
			}
		});
	}
}