@Override
    public boolean equals(Object obj) {
	if (this == obj)
	    return true;
	if (obj == null)
	    return false;
	if (getClass() != obj.getClass())
	    return false;
	AvaWorldImpl other = (AvaWorldImpl) obj;
	if (objects == null) {
	    if (other.objects != null)
		return false;
	} else if (!objects.equals(other.objects))
	    return false;
	if (size == null) {
	    if (other.size != null)
		return false;
	} else if (!size.equals(other.size))
	    return false;
	return true;
    }