Hibernate GenericDAO using Class-Mate

HibernateGenericDAO

    class Device {}
    class Router extends Device {}

    class GenericDAO<T, ID extends Serializable> {
        protected Class<T> persistentClass;
        protected Class<ID> idClass;

        private GenericDAO() {
            List <ResolvedType> typeParameters = new TypeResolver().resolve(this.getClass()).typeParametersFor(GenericDAO.class);
            this.persistentClass = (Class<T>) typeParameters.get(0).getErasedType();
            this.idClass = (Class<ID>) typeParameters.get(1).getErasedType();
        }
    }

    class DeviceDAO<T extends Device> extends GenericDAO<T, Long> {}
    class RouterDAO extends DeviceDAO<Router> {}

    @Test
    public void resolvesEntityType () {
        RouterDAO routerDAO = new RouterDAO();
        assert routerDAO.persistentClass == Router.class;
        assert routerDAO.idClass == Long.class;
    }