I have created 2 entities. Now when I retrieve my entities in my backend I verify some things, but when my backend return those entities to my frontend the hibernate try to upd
You already got the pieces in the comments, but let me put it together in an answer:
I think it`s because I change some data in my entity while i do my logic
That interpretation is correct.
If you load an entity via JPA it is attached to a session and every change to it gets tracked and written to the database once you close the session/ commit the transaction.
In order to avoid that you need to remove the entity from the session. You can do that by either
detaching the entity from the persistence context: https://docs.oracle.com/javaee/7/api/javax/persistence/EntityManager.html#detach-java.lang.Object-
closing the EntityManager / transaction before doing the manipulation. This basically means doing your changes to the entity outside the outer most method annotated with @Transactional
Note that in both cases lazy loading won't work anymore so you'll have to make sure you loaded everything you needed before detaching the entity.