@RequestMapping("/admin/ajax/product-variants/list-product-variants")
  @ResponseBody
  public Map<String, Object> listProductVariants(
      @RequestParam(defaultValue = "", required = false) String start,
      @RequestParam(defaultValue = "", required = false) String limit,
      HttpServletRequest request) {

    start = StringUtils.hasLength(start) ? start : "0";
    limit =
        StringUtils.hasLength(limit)
            ? limit
            : configurationService.getConfigurationValue(
                ConfigConstant.KEY_MAX_DISPLAY_SEARCH_RESULTS);
    int languageId = getCurrentLanguage(request).getId();
    Map<String, Object> response = new HashMap<String, Object>();
    response.put(DesktopConstant.EXT_JSON_READER_TOTAL, productVariantService.getTotal(languageId));
    response.put(
        DesktopConstant.EXT_JSON_READER_ROOT,
        productVariantService.getVariantsGroups(languageId, start, limit));
    return response;
  }