What kind of difficulties you've faced with Hibernate

Question

As any other framework Hibernate impose some restrictions. One of a very popular interview questions is:

"What kind of difficulties you've faced with Hibernate?"

For instance:

1. Lazy one-2-one bidirectional is impossible.
2. Lazy collection loading after session close. That happens when you use DAO + Spring transactions. You can read here about it.
3. Troubles with concurrent update on clustered application
4. N + 1 selecting problem

Question: may you supplement this humble list please?

P.S. I don't mean those difficulties when you are newcomer in Hibernate and don't now how to map many-2-many. I mean those difficulties that faced every experienced programmer while using this framework.

Answer 1

I would add :

• Managing the session lifecycle and transaction demarcation (particulary with RIA apps using long-conversation scope which cannot be managed by the container)
• collection management and performance (Collection mapping)
• The JPA hashCode() / equals() dilemma