Stop zombies from spawning naturally?

I'm trying to make something where zombies can only be spawned by Bukkit, I tried using UUIDs and Hashmaps but I couldn't find out how to get a zombies UUID before it actually spawns.

All help greatly appreciated.

 

You wan't zombies not to spawn but then you do? not sure what your wanting here.

 

Try to get the Spawn Reason.



I think naturally spawned have other spawn reasons than Egg spawned

 

Yeah I ended up working it out using this

Code:java

    @EventHandler
    public void onCreatureSpawn(CreatureSpawnEvent event){
        EntityType type = event.getEntityType();
        if(type == EntityType.ZOMBIE){
            if(event.getSpawnReason() != SpawnReason.CUSTOM){
                event.setCancelled(true);
            }
        }
    }