@Override
public boolean equals(Object o) {
    if (this == o) return true;
    if (!(o instanceof SimpleObject)) return false;
    SimpleObject that = (SimpleObject) o;
    // we prefer the method versions of accessors,
    // because of Hibernate's proxies.
    if (getId() != null ?
        !getId().equals(that.getId()) : that.getId() != null)
        return false;
    if (getKey() != null ?
        !getKey().equals(that.getKey()) : that.getKey() != null)
        return false;
    if (getValue() != null ?
        !getValue().equals(that.getValue()) : that.getValue() != null)
        return false;
    return true;
}
@Override
public int hashCode() {
    int result = getId() != null ? getId().hashCode() : 0;
    result = 31 * result + (getKey() != null ? getKey().hashCode() : 0);
    result = 31 * result + (getValue() != null ? getValue().hashCode() : 0);
    return result;
}



@Test
public void testSaveLoad() {
    Long id = null;
    SimpleObject obj;
    try (Session session = SessionUtil.getSession()) {
        Transaction tx = session.beginTransaction();
        obj = new SimpleObject();
        obj.setKey("sl");
        obj.setValue(10 L);
        session.save(obj);
        assertNotNull(obj.getId());
        // we should have an id now, set by Session.save()
        id = obj.getId();
        tx.commit();
    }
    try (Session session = SessionUtil.getSession()) {
        // we're loading the object by id
        SimpleObject o2 = session.load(SimpleObject.class, id);
        assertEquals(o2.getKey(), "sl");
        assertNotNull(o2.getValue());
        assertEquals(o2.getValue().longValue(), 10 L);
        SimpleObject o3 = session.load(SimpleObject.class, id);
        // since o3 and o2 were loaded in the same session, they're not only
        // equivalent - as shown by equals() - but equal, as shown by ==.
        // since obj was NOT loaded in this session, it's equivalent but
        // not ==.
        assertEquals(o2, o3);
        assertEquals(obj, o2);
        assertTrue(o2 == o3);
        assertFalse(o2 == obj);
    }
}