如何正确使用Struts ActionForms，Value Objects和Entities？

I've inherited a large Java app that uses Struts, Spring, and Hibernate. The classes and interfaces I deal with daily are: Struts Actions, Struts ActionForms, Value Objects, Service Interfaces and Implementations, DAO Interfaces and Implementations, and Entities. I'm pretty clear on the how and why of most of these, except I'm unsure about the correct separation of responsibilities between the ActionForms, Value Objects, and Entities. I should also mention that the Domain Model (i.e. all of the entities) doesn't contain much (if any) real business logic. This is essentially a CRUD app and most of the real logic is in the database (yuck!). Anyway, there are several distinct Java related issues that I'm wondering about:I've inherited a large Java app that uses Strut