Transactional annotation different behavior

Question

I just saw two different projects.

In one of them whenever you tried to persist/save an entity from a method with no @Transactional annotation there was an exception that said: No session found

On the other

Even though no @Transactional annotation exists the save method allows saving.

PS - One project uses Spring + Hibernate (with session not found exception), the other uses Spring + JPA + Spring Data repositories (allows saving with no transactional annotation)

Any ideas why the differences? What's the best practice?

Answer 1

That's because, as the documentation of Spring Data JPA indicates

CRUD methods on repository instances are transactional by default. For reading operations the transaction configuration readOnly flag is set to true, all others are configured with a plain @Transactional so that default transaction configuration applies. For details see JavaDoc of Repository.