Strange behaviour with GregorianCalendar

Question

I just encountered a strange behaviour with the GregorianCalendar class, and I was wondering if I really was doing something bad.

This only appends when the initiali

Answer 1

Calendar starts with current day - 31 may 2010 in your example. When you set month to February, date changes to 31 February 2010 which normalized to 3 March 2010, so cal.getActualMaximum(Calendar.DAY_OF_MONTH) returns 31 for March.

Calendar c = Calendar.getInstance();
c.set(Calendar.YEAR, 2010);
c.set(Calendar.MONTH, Calendar.MAY);
c.set(Calendar.DAY_OF_MONTH, 31);
System.out.println(c.getTime());
c.set(Calendar.MONTH, Calendar.FEBRUARY);
System.out.println(c.getTime());

output:

Mon May 31 20:20:25 GMT+03:00 2010
Wed Mar 03 20:20:25 GMT+03:00 2010

To fix you code, you can add cal.clear(); or set day 1..28 before setting month