public Set<Hotel> getReservationsWithUser(int userId)
{
Query query = this.entityManager.createQuery("select u from User u where u.id=:id");
query.setParameter("id", userId);
User user = (User)query.getSingleResult();
Set<Hotel> hotels = new HashSet<Hotel>();
Set<Reservation> reservations = user.getReservations();
for(Reservation reserve : reservations)
{
hotels.add(reserve.getHotel());
}