code: @Nullable
    public Date getTimeOfDayForDate (final Date dateTime)
    {
      if (dateTime == null)
        return null;
      final Calendar cal = PDTFactory.createCalendar ();
      cal.setTime (dateTime);
      cal.set (Calendar.HOUR_OF_DAY, m_nHour);
      cal.set (Calendar.MINUTE, m_nMinute);
      cal.set (Calendar.SECOND, m_nSecond);
      cal.clear (Calendar.MILLISECOND);
      return cal.getTime ();
    }
docs: Return a date with time of day reset to this object values. The millisecond
  value will be zero.