code: public static String serialize(List<ServiceRequester> requesterList) throws IOException {
      String jsonList = objectMapper.writeValueAsString(requesterList);
      String base64Str = Base64.getEncoder().encodeToString(jsonList.getBytes("UTF-8"));
      return URLEncoder.encode(base64Str, "UTF-8");
    }
docs: <p> This implementation converts a given list to a json string.
  Due to json string may have reserved keyword that can confuse
  {@link Config}, we first use Base64 to encode the json string,
  then use URL encoding to remove characters like '+,/,='.