If I modify a Hibernate entity, after doing a save, when I commit would the changes be saved to the database

Question

If in Hibernate, I do the following steps:

1. Open a session.
2. Create a new hibernate POJO object (that is to be saved), and fill in the values.
3. Now I do session.save().
4. Now I change the POJO object - say it is an employee object and I do emp.setName("Other Name") i.e change the name of the employee in the object.
5. Now I do a transaction commit.

My question is what would be saved to the database - the name before I did session.save() or the name after the change i.e. "Other Name"?

Answer 1

The moment you saved the entity, it becomes managed and all further changes are propagated to the database during Session.flush.

When you saved the entity, you only triggered an EntityInsertAction to be queued. After you changed the entity, the current entity state was changed so during a flush, Hibernate will simply insert the latest entity state, so the database will contain the "Other Name".

In fact, calling a method like save for a managed entity (which triggers an entity merge) is actually going to affect performance.

Answer 2

While working with managed entity, when you don't call save, it will be saved automatically.