>The application may concurrently access the same persistent >state in two different sessions. However, an instance of a >persistent class is never shared between two Session instances. >Hence there are two different notions of identity:
>Then for objects returned by a particular Session, the two >notions are equivalent. However, while the application might >concurrently access the "same" (persistent identity) business >object in two different sessions, the two instances will >actually be "different" (JVM identity).
>This approach leaves Hibernate and the database to worry about >concurrency (the application never needs to synchronize on any >business object, as long as it sticks to a single thread per >Session) or object identity (within a session the application >may safely use == to compare objects).