player get killer

package com.vlad.tutorial.commands;

import org.bukkit.Material;
import org.bukkit.entity.Entity;
import org.bukkit.entity.EntityType;
import org.bukkit.entity.Player;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.entity.EntityDeathEvent;
import org.bukkit.inventory.ItemStack;

public class Dragon implements Listener {
    @EventHandler
  public void onDeath(EntityDeathEvent e){
    Entity entity = e.getEntity();
    Entity killer = e.getEntity().getKiller();

    if (entity.getLastDamageCause() instanceof Player){
            Player p = (Player) e.getEntity().getKiller();
            if (entity.getType().equals(EntityType.ZOMBIE)) {
                p.getPlayer().getInventory().addItem(new ItemStack(Material.DRAGON_EGG, 1));
            }
    }
  }
}