I have a very simple hibernate class with an id class that contiains four variables. I am using createcreria like below. If I run the sql that is printed in the log, I get six rows. Two rows contain a null value in one of the id variables. (which should be fine). The return list contains six items, but two of the items are null. I would have expected six objects with the one variable null. whats wrong.

Criteria criteria = session.createCriteria(StockInventory.class)
.add(Expression.eq("id.reference", reference));
return criteria.list();