public class Eier {

    public Eier() { }

    HashMap<Integer, Ei> eier = new HashMap<Integer, Ei>();

    public int spawnEgg(Location loc) {
        int id = getUnusedID();
        Ei ei = new Ei(loc);
        eier.put(id, ei);
        return id;
    }

    private int getUnusedID() {
        int i = new Random().nextInt(100);
        if (!eier.containsKey(i)) return i;
        return getUnusedID();
    }
}