private static @NotNull String getCalendarValue(final Calendar calendar, final int field) {
    int val = calendar.get(field);
    if (field == Calendar.MONTH) val++;
    final String result = Integer.toString(val);
    if (result.length() == 1) {
      return "0" + result;
    }
    return result;
  }
private static @NotNull String getCalendarValue(final Calendar calendar, final int field)