@Entity
@Table(name = "MY_TABLE")
@DiscriminatorColumn(name = "DISC_COL", discriminatorType = DiscriminatorType.INTEGER)
@DiscriminatorValue("0")
@Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
public class ParentEntity {

	@Id
	@GeneratedValue(strategy = GenerationType.AUTO)
	@Column(name = "ID")
	Integer id;

	@JoinColumn(name = "PARENT", foreignKey = @ForeignKey(name = "FK_PARENT_01"))
	@ManyToOne
	@Fetch(FetchMode.SELECT)
	ParentEntity parent;
}

@Entity
@DiscriminatorValue("1")
public class ChildEntity extends ParentEntity {}

public class ORMUnitTestCase extends BaseCoreFunctionalTestCase {

	// Add your entities here.
	@Override
	protected Class<?>[] getAnnotatedClasses() {
		return new Class<?>[] { ParentEntity.class, ChildEntity.class };
	}

	// Add in any settings that are specific to your test. See
	// resources/hibernate.properties for the defaults.
	@Override
	protected void configure(Configuration configuration) {
		super.configure(configuration);

		configuration.setProperty(AvailableSettings.SHOW_SQL, Boolean.TRUE.toString());
		configuration.setProperty(AvailableSettings.FORMAT_SQL, Boolean.TRUE.toString());
		configuration.setProperty(AvailableSettings.DEFAULT_BATCH_FETCH_SIZE, "10");
	}

	// Add your tests, using standard JUnit.
	@Test
	public void hhh0000Test() throws Exception {
		// BaseCoreFunctionalTestCase automatically creates the SessionFactory and
		// provides the Session.
		ChildEntity child1 = new ChildEntity();
		ChildEntity child2 = new ChildEntity();
		try (Session s = openSession()) {
			Transaction tx = s.beginTransaction();

			child1.parent = child2;

			s.persist(child1);
			s.persist(child2);
			tx.commit();

			// To simulate that all data was already persisted before the application starts
			s.getSessionFactory().getCache().evictAllRegions();
		}

		try (Session s = openSession()) {
			Transaction tx = s.beginTransaction();
			ParentEntity entity = s.byId(ParentEntity.class).load(child1.id);
			assertThat(entity.parent).isInstanceOf(ChildEntity.class);
			tx.commit();
		}
	}
}