Fine-grained object model in hibernate

In the Hibernate in Action (Manning publication),

A major objective of the Hibernate project is support for fine-grained object models, which we isolated as the most important requirem开发者_如何学Pythonent for rich domain model. In crude term, fine-grained means "more classes than table".

I don't get this... Please some body help on this.

This refers (I think) to what Hibernate calls "components", and what JPA calls "embedded classes". See the link for an explanation of what that means.