Two entities coexisting in one table
I have stumbled across small problem. I had an abstract class, which aggregated all mutual properties of an object and two concrete classes. One did not need any additional fields, while the other needed another relation. Idea was to create one table and gather both those concrete objects from it. I have never done it before, so it was interesting thing to discover. I was working on Team abstraction. Team is a collection of heroes. But teams can be lead by someone or self-organized, hence I have three classes, like so: Notes: BaseTeam is an abstract class annotated with @MappedSuperclass . Since it is abstract I cannot instantiate it and with annotation all its properties will be passed to class extending it. Team class is a concrete class extending BaseTeam. It inherits all the properties from its superclass and does not define any new. It is annotated with @Entity and @Table with filled name property. It is important to fill those properties, so concrete class can recogn