code: public XMLGregorianCalendar newGMonthDay(int month, int day) {
          XMLGregorianCalendar cal=dataFactory.newXMLGregorianCalendar();
          cal.setMonth(month);
          cal.setDay(day);
          return cal;
      }
docs: /*
  (non-Javadoc)
  @see org.openprovenance.prov.model.LiteralConstructor#newGMonthDay(int, int)