@Path("{id}") @PUT @Consumes("application/json") @Produces("application/json") public Organization edit(OrganizationDTO dto, @PathParam("id") Long id) { // lookup entity from database Organization org = entityManager.find( Organization.class, entity.getId() ); // map changable values to the entity org.setName( dto.getName() ); org.setDescription( dto.getDescription() ); org.setUser( entityManager.find( User.class, userId ) ); dto.setUser( org.getUser() ); // merge changes entityManager.merge( org ); // return dto return dto; }