4.2.4. Prefer Optional Non-final Classes

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. You will not, however, be able to use proxies for lazy association fetching which will ultimately 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 proxying by setting lazy="false".