I discovered the annotation @MappedSuperClass which does exactly what I intend to achieve. However; there is a new situation with this.
I now have a class (@MappedSuperClass) called MappedClass which an @Entity called Entity extends. I now want to extend Entity with another @Entity called TransactionEntity, but this results in the error message: The type Entity cannot be the superclass of TransactionEntity; a superclass must be a class
This is not what the final draft on persistence states:
Both abstract and concrete classes can be entities. Entities may extend non-entity classes as well as
entity classes, and non-entity classes may extend entity classes.
Is there a way to achieve a @MappedSuperClass with several subs which is entites?
Bug searching and testing of the @MappedSuperClass ensures me that it works as I hoped.
I am sorry for using thread space for such errors when my frustration growed after reading x documents.
The compiler error (which was indeed strange) was my own fault (who else). In my source I used "extend Entity" which made the compiler think that I was trying to extend javax.persistence.Entity and not the Entity class in my package.