Yesterday I downloaded Hibernate 3.3.1.GA and tried it with our application (in our production version we are using 3.2.6.GA).

I soon ran into an exception which is not thrown using version 3.2.6. We have some basic read only data in our application, i.e. status entities. These entities do not change and therefore are held in cache marked as READ_ONLY. Now there is a curious situation with Hibernate 3.3.1: on some business entities which hold a relation to one of those read only entities, everything works as in version 3.2.6; on other entities we now get an exception when we call the JPA merge() operation to update or insert the object. The method


throws an exception:



Curiously: the complained entity "Feature" is not directly used by the business object, but only referenced indirectly by it's "child" which itself is used by the business object to be saved.

Can anyone of the Hibernate experts explain why this is done and under what conditions? As I said, we are using the complained Feature object with other business objects, and on their merge()-call the READ_ONLY object has no merge event (I tested it with a break point at onMerge).

I just had another look on my class and saw, that I put the annotation

on the entity which was complained as of State.READ_ONLY.

Now I commented this annotation out, and after restart of the app, I retried and noticed to my BIG surprise, that the error is not there anymore.

Okay, can anyone explain what's the effect of this annotation? Until now, I thought it was just a hint to Hibernate to get some performance hints.

BTW: I also have this annotation on my basic data entity