How to set the target of a monster/animal?

I tried many different ways, also looked into the source of other plugins, but somehow none of them works.. I can't set a zombies target.

Example:

Code:

@EventHandler
    public void moveDetection(PlayerMoveEvent evt) {
 
            Player p = evt.getPlayer();
            List<Entity> zombies = p.getNearbyEntities(30, 30, 30);
                LivingEntity spieler = p;
                for (Entity e : zombies) {
                    if (e instanceof Zombie) {
                        ((Zombie) e).setTarget(spieler);
          }
        }
    }

Thanks in advance!

 

becaus the setTarget() method is bugged, it doesnt work, not on hostile, or passive mobs
did alot of research on it myself

 

yes, read it too, but there are plugins which are using this method^^
for example: http://dev.bukkit.org/server-mods/monster-apocalypse/