The work for OPENDJ-7853 required to make Resource non-final in order to be able to subclass it.
Looking a bit more into it, it looks like this subclassing is not really necessary. We can remove this subclassing (and add back the final keywork on the Resource class) if we:
- constrain the ReferencePropertyMapper to only accept ObjectPropertyMapper (instead of the more general PropertyMapper)
- add a new constructor to the Resource class that accepts an ObjectPropertyMapper
This issue can be closed once implemented as suggested.