When Hibernate flushes a Session, how does it decide which objects in the session are dirty?

Question

My understanding of Hibernate is that as objects are loaded from the DB they are added to the Session. At various points, depending on your configuration, the session is flu

Answer 1

Hibernate takes a snapshot of the state of each object that gets loaded into the Session. On flush, each object in the Session is compared with its corresponding snapshot to determine which ones are dirty. SQL statements are issued as required, and the snapshots are updated to reflect the state of the (now clean) Session objects.