@Entity
@Audited
@Inheritance(strategy = InheritanceType.SINGLE_TABLE)
// Omitted @DiscriminatorColumn and @DiscriminatorValue annotations.
public class Car implements Serializable {
	@Id
	private Long id;

	private String vin;

	public Car() {
	}

	public Car(Long id, String vin) {
		this.id = id;
		this.vin = vin;
	}

	// getters & setters...
}

@Entity
@Audited
@DiscriminatorValue(value = "SPORT_CAR")
public class SportCar extends Car implements Serializable {
	private Integer maximumSpeed;

	public SportCar() {
	}

	public SportCar(Long id, String vin, Integer maximumSpeed) {
		super( id, vin );
		this.maximumSpeed = maximumSpeed;
	}

	// getters & setters...
}

// Revision 1
em.getTransaction().begin();
Car car = new Car( 1L, "1M8GDM9AXKP042788" );
em.persist( car );
em.getTransaction().commit();
// Revision 2
em.getTransaction().begin();
SportCar sportCar = new SportCar( 2L, "2N8GDM5AXKY0427I8", 200 );
em.persist( sportCar );
em.getTransaction().commit();
// Revision 3
em.getTransaction().begin();
sportCar = em.find( SportCar.class, 2L );
sportCar.setVin( "1M8GDM9AXKP042789" );
sportCar = em.merge( sportCar );
em.getTransaction().commit();