OK, after thinking about it a little more and studying the code, I understand your point of avoiding to create a dependency between -engine and ORM. Moreover, the code is going to be ugly with hardcoded class names and so on.

Right. JPA is optional, so if we are going down the path of trying to understand more JPA mapping information (by checking for @MappedSuperclass and co) we need to make it string based.

we collect all the collection roles in the parseContext;
we add all the collectionRoles of the parents to the inheriting classes so all the collection roles collected so far because we analyze the hierarchy top down.

Not quite sure I follow.