Should I often call EntityManager.clear () to avoid memory leaks?

Question

I'm new to JPA / OpenJPA, and I noticed that if I don't call EntityManager.clear() after I leave the objects, I get OutOfMemoryError (I keep adding new entities to the loop). I'm not sure if this is the expected behavior, or just, and the problem is with OpenJPA 1.2.1.

So, do I need to explicitly separate objects from myself? If I'm not, is that good practice anyway?

Answer 1

I do not have much experience with JPA. However, it will be useful -
In JPA, you must: - Create a new EntityManager for each transaction.
- Call clear () after each transaction to clear the persistence context.

Answer 2

Depends on the number of objects that you enter in the read process. If you are processing large numbers (or some of them are large), then using clear () may make sense. Each time an object is read, it must be placed in the L1 cache using JPA impl.

Answer 3

There seems to be something wrong with your design. Typically, an object is separated when it goes beyond the object manager. And this is one of the reasons that you cannot lazy load relationships, out of scope.

As for my experience, I rarely used em.clear (), if ever. I used the implementation of Hibernate and Toplink Essentials. No experience with OpenJPA yet.