Script aCis 382 Spawn/Despawn Monster when Boss is Alive

package net.sf.l2j.gameserver.scripting.scripts.custom;

import java.util.ArrayList;
import java.util.List;

import net.sf.l2j.gameserver.model.World;
import net.sf.l2j.gameserver.model.actor.Npc;
import net.sf.l2j.gameserver.model.actor.Player;
import net.sf.l2j.gameserver.scripting.Quest;

public class FafurionGhostEvent extends Quest
{
    private static final int BOSS_ID = 210;
    private static final int[] GHOST_IDS = {207, 208, 209, 211, 212};

    // Ghost spawn coordinates: x, y, z, heading
    private static final int[][] GHOST_LOCS = {
            {212000, 120000, -3700, 0},
            {213000, 119500, -3650, 0},
            {211500, 118800, -3720, 0},
            {212500, 119000, -3680, 0},
            {213200, 118500, -3660, 0}
    };

    private final List<Npc> spawnedGhosts = new ArrayList<>();

    public FafurionGhostEvent()
    {
        super(-1, "custom");

        addSpawnId(BOSS_ID);
        addKillId(BOSS_ID);
    }
    private Npc addSpawn(int npcId, int x, int y, int z, int heading, boolean unused1, int unused2)
    {
        addSpawn(npcId, x, y, z, heading);


        return null;
    }

    private void addSpawn(int npcId, int x, int y, int z, int heading) {
    }

    @Override
    public String onSpawn(Npc npc)
    {
        if (npc.getNpcId() == BOSS_ID)
        {
            for (int i = 0; i < GHOST_IDS.length; i++)
            {
                int ghostId = GHOST_IDS[i];
                int[] loc = GHOST_LOCS[i % GHOST_LOCS.length];

                Npc ghost = addSpawn(ghostId, loc[0], loc[1], loc[2], loc[3], false, 0);
                if (ghost != null)
                {
                    spawnedGhosts.add(ghost);
                }
            }
            System.out.println("FafurionGhostEvent: Spawned ghosts because boss spawned.");
        }
        return null;
    }



    
    public String onKill(Npc npc, Player killer, boolean isPet)
    {
        if (npc.getNpcId() == BOSS_ID)
        {
            for (Object obj : World.getInstance().getObjects())
            {
                if (obj instanceof Npc)
                {
                    Npc ghost = (Npc) obj;
                    int id = ghost.getNpcId();
                    if (id == 207 || id == 208 || id == 209 || id == 211 || id == 212)
                        ghost.deleteMe();
                }
            }
            System.out.println("FafurionGhostEvent: Despawned ghosts because boss died.");
        }
        return null;
    }



    public static void main(String[] args)
    {
        new FafurionGhostEvent();
    }
}