The session interface is the primary interface used in Hibernate Application. It is single threaded sort-lived object and represents conversation between Application and the persistent store. It helps to create query objects to retrieve persistent objects.
You can get the session object from session factory
Session session = sessionFactory.openSession();
Session Interface role:
--Wraps a JDBC connection
--Factory for Transaction
--Holds a mandatory (first-level) cache of persistent objects, used when navigating the object graph or looking up objects by identifier