Entity class requirement

•Must be annotated with @Entity
•Must have public or protected no-arg constructor.
•Class must not be declared final. No methods or persistent instance variables must be declared final.
•If an entity is passed by value as detached object, such as through remote session bean interface, then the class must implement java.io.Serailizable
•Entity may extend both entity and non-entity classes, and non-entity classes may extend entity classes
•Persistent instance variable CANNOT be public (can be either private, protected or package)