Question

Is there a way to check if two EntityManagers instances represents the same PersistenceContext?

The container can use a proxy for implementation of the EntityManager, so I don’t think that checking the reference of the injected EntityManager and comparing it (in other words doing “==” comparison) is enough to say that it represents the same PersistenceContext, right?

Answer 1

I have debugged the scenario with two entity managers with @PersistenceContext

• When injected persistent context with same unit, comparing entityManager.getDelegate() which returns the vendor specific underlying object are same & both points to the same entity manager factory.

• With different units, the delegates obtained & entity manager factory, both were different.

Further can refer this post.

Note : The environment used is Java EE 5, there were several other methods like getMetaModel(), unwrap(object), getProperties() etc. can provide further information.