code: public static LocalDateTime toLocalDateTime(final Calendar self) {
          return LocalDateTime.of(toLocalDate(self), toLocalTime(self));
      }
docs: Converts the Calendar to a corresponding {@link java.time.LocalDateTime}. If the Calendar has a different
  time zone than the system default, the LocalDateTime will be adjusted into the default time zone.
  
  @param self a Calendar
  @return a LocalDateTime
  @since 2.5.0