Hibernate/JPA: Is it possible to retrieve heterogeneous entities in a single query?

Question

I have 2 entities: EntityA and EntityB.

They are unrelated, and I cannot put them in a Inheritance tree for some restrictions out of the scope of this question.

Answer 1

Well, I finally figured it out.

It is enought to make the entities implement a common interface (it is not even needed to declare this interface on Hibernate).

Then, a query like this can be done:

FROM my.package.CommonInterface obj
WHERE obj IN (FROM EntityA WHERE fieldA=1) OR
      obj IN (FROM EntityB WHERE fieldB='a')

This way, you retrieve a List.

Problem solved.