When we use PersistenceContextType.TRANSACTION
changes we make to a disconnected entity wont be visible if we again obtain the entity using its id
and these changes will be lost if we update the freshly gotten same entity and save it.
This is because the freshly gotten entity is got by executing a select.
Further more if lazy fields had not been obtained when connected after a disconnect attempting to access the lazy field will give lazy initialization exception.

When we use PersistenceContextType.EXTENDED
changes we make to a disconnected entity will be visible if we again obtain the entity using its id
and these changes will be not lost if we update the freshly gotten same entity and save it.
This is because the freshly gotten entity is NOT got by executing a select.
Further more if lazy fields had not been obtained when connected after a disconnect attempting to access the lazy field will NOT give lazy initialization exception.

So need to learn about the entity cache. Any pointers?

getReference and find.
We should use EntityManager.getReference when we need state to be lazily fetched where permitted (Define permitted).
Will using EntityManager.find method really get all the fields? Where dioes it stop.

When is lazy permitted?
Marking a joined entity as EAGER in orm.xml is still keeping it lazy when parent entity is accessed by getReference. Why?