In he famous book "Java persistence with Hibernate" we can read the following:

*"A persistence context is a cache of persistent entity instances.... Automatic dirty checking is one of the benefits of this caching. Another benefit is repeatable read for entities and the performance advantage of a unit of work-scoped cache... You don’t have to do anything special to enable the persistence context cache. **It’s always on and, for the reasons shown, can’t be turned off**.*

Does this mean that one can never achieve a transaction isolation level "Read uncommitted" with Hibernate?