Java traverses all dates of a month

Method of Tool class

Gets the number of days for the specified month public
    static int getdaysbyyearmonth (int month) {

        Calendar a = Calendar.getinstance ();
        A.set (Calendar.year, year);
        A.set (Calendar.month, month-1);
        A.set (calendar.date, 1);
        A.roll (Calendar.date,-1);
        int maxdate = A.get (calendar.date);
        return maxdate;
    }

Second, traverse

    public void Dayreport (Date month) {

        Calendar cal = Calendar.getinstance ();
        Cal.settime (month);//month for a specified month any date
        int year = Cal.get (calendar.year);
        int m = Cal.get (calendar.month);
        int daynumofmonth = Timeutils.getdaysbyyearmonth (year, m);
        Cal.set (Calendar.day_of_month, 1);//starting from A for

        (int i = 0; i < daynumofmonth i++, Cal.add (calendar.date, 1)) {
  
   date d = cal.gettime ();
            SimpleDateFormat SimpleDateFormat = new SimpleDateFormat ("Yyyy-mm-dd");
            String df = Simpledateformat.format (d);
      }
    }