Return the underlying EntityManager that this proxy will delegate to.
In case of an extended EntityManager, this will be the associated
raw EntityManager.
In case of a shared ("transactional") EntityManager, this will be
the raw EntityManager that is currently associated with the transaction.
Outside of a transaction, an IllegalStateException will be thrown.
the underlying raw EntityManager (never null ) throws: IllegalStateException - if no underlying EntityManager is available |