code: static private final Date parseISODate(String stringValue)
    {
      try
      {
        return getDateFormat().parse(stringValue);
      }
      catch (ParseException pe)
      {
        if (LOG.isLoggable(Level.INFO))
        {
          LOG.log(Level.INFO, "CANNOT_PARSE_VALUE_INTO_DATE_WITH_YYYY_MM_DD_PATTERN "+ stringValue, pe);
        }
        return null;
      }
    }
docs: Parse a string into a java.util.Date object.  The
  string must be in ISO 9601 format (yyyy-MM-dd).
  @todo why not throw the exception in a different format?
  why do we kill it here and return null?