code: public static final Parser<Date> instance() { // NOPMD it's thread save!
      if (MonthParser.instanceParser == null) {
        synchronized (MonthParser.class) {
          if (MonthParser.instanceParser == null) {
            MonthParser.instanceParser = new MonthParser("yyyy-MM");
          }
        }
      }
      return MonthParser.instanceParser;
    }
docs: returns the instance.
  
  @return Parser