Spring Data JPA inheritance in repositories

Question

I have an abstract class annotated with @MappedSuperClass. There are around 15 entities that extend this abstract class (having 15 corresponding tables in the d

Answer 1

Ideally, the following set up should work:

Entity classes

@Entity
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)
public abstract class Equipment { ... }

@Entity
public class Crane extends Equipment {}

@Entity
public class Excavator extends Equipment {}

Repository interface

public interface EquipmentRepository extends CrudRepository {}

Repository consumer

@Service
public class SomeService {
  @Autowired
  private EquipmentRepository craneRepository;

  @Autowired
  private EquipmentRepository excavatorRepository;
}

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I have set up a sample project on Github to demonstrate this in action. Running Maven tests as any of the following will show passing tests to demonstrate that the set up works as expected.

mvn test -Dspring.profiles.active="default,eclipselink"

mvn test -Dspring.profiles.active="default,openjpa"

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That said, this set up may not work with Hibernate, which is what I suspect you are using. Hibernate does not support auto-incremented identifier columns with TABLE_PER_CLASS inheritance. Therefore, attempting to run the set up above with Hibernate will throw an exception. This can be verified by running the following on the sample linked above.

mvn test -Dspring.profiles.active="default,hibernate"