I don't know what is your target goal, there are a lot of critical items can make a solution good  or bad.
Is this a theoretical question or not ? If it is not do u make a framework or something else ? did u consider performance aspects of desired technologies or not ? r u sure about loading a collection (maybe a large collection) just to get size  of it ? don't u need to use something like extra-lazy in hibernate ( if you use hibernate as an ORM) !!!!

however i can just say you should apply proxy pattern ( even you use AOP techniques, you are applying proxy pattern indirectly)
and maybe this link can be helpful for you (to make your mind better ): http://www.hibernate.org/377.html (Remote Lazy Loading)