Its in
http://www.hibernate.org/hib_docs/v3/re ... erence.pdf
4.1.3. Prefer non-final classes (optional)
A central feature of Hibernate, proxies, depends upon the persistent class being either non-final, or the implementation
of an interface that declares all public methods.
You can persist final classes that do not implement an interface with Hibernate, but you won't be able to use
proxies for lazy association fetching - which will limit your options for performance tuning.
You should also avoid declaring public final methods on the non-final classes. If you want to use a class
with a public final method, you must explicitly disable ------proying----- by setting lazy="false".
So what is proying ????