The above diagram regarding "EntityManager", "Session" and "SessionImpl" seems wrong.
We should change it into something as below:
The issue is the ‘session’ suite diagram is confusing for it implies it is special or different from the other two suites. That confuses user guide reader a lot.
I further confirmed with the svg original author (i.e. Vlad). He told me “The SVG was taken with IntelliJ IDEA 5 years ago when the EntityManagerImpl was having a reference to the Session. But, that's not the case anymore since the Session implements EntityManager.”