@Transactional(readOnly = false) @RequestMapping( value = "/edit", method = {RequestMethod.POST, RequestMethod.GET}) public void editor( @RequestParam String oper, @RequestParam(required = false) Long id, Contact contacts, BindingResult result, HttpServletResponse response) throws IOException { if (result.hasErrors()) { response.sendError(400, result.toString()); return; } switch (oper) { case "add": contactRepository.save(contacts); response.setStatus(200); break; case "edit": Contact fromDB = contactRepository.getOne(contacts.getContactId()); if (fromDB != null) { if (contacts.getVersion() >= fromDB.getVersion()) { contactRepository.save(contacts); response.setStatus(200); } else { response.sendError(406, "ANOTHER TRANSACTION MODIFICATION"); } } else { response.sendError(406, "NO CONTACT TYPE FOUND"); } break; case "del": if (id != null) { contactRepository.delete(id); response.setStatus(200); } break; default: response.sendError(406, "UNKNOWN OPERATION"); } }