One of our developers had the following type of code in place:

Parent parent = new Parent();
dao.create(parent);
Child child = new Child();
parent.getChildren().add(child);
dao.saveOrUpdate(parent);
dao.create(child);


All of this code worked!  We never noticed the error until we put a Hibernate wrapper in play that has asserts for all kinds of extraneous conditions.  In the above code the child has not been created in Hibernate yet.

So, why did it work in straight Hibernate?  We think it didn’t work and only gave a silent error/exception.  All of this would be cleaned up later as a cleanup task by the create(child) call or the even later flush() call.

Of course, once we switched the order of the create(child) call with the saveOrUpdate(parent) it all worked.

We had noticed similar silent errors for delete() calls as well.