Strange problem with DATE

Question

Hi,
I am having a strange problem in the following piece of code :
this._calendar = new GregorianCalendar();
this._calendar.set(Calendar.YEAR, 2001);
System.out.println("definition 152 " + this._calendar.get(Calendar.YEAR));
this._calendar.set(Calendar.MONTH, 12);
this._calendar.set(Calendar.DATE, 13);
this._calendar.set(Calendar.HOUR, 9);
this._calendar.set(Calendar.MINUTE, 34);
this._calendar.set(Calendar.SECOND, 45);
this._calendar.set(Calendar.MILLISECOND, 928);
System.out.println("definition 153 " + this._calendar.get(Calendar.YEAR));
String dateform = dateformatter.format(_calendar.getTime());
System.out.println("definition 155 " + dateform);
I get the output
definition 152 2001
definition 153 2002
definition 155 2002.01.03 12:11:14.928
How the year changes from 2001 to 2002 is a mystery. However if I change the month to 6 then the behaviour is different.
Any ideas as what is going on???????????

Answer 1

Hi,
I am having a strange problem in the following piece
of code :
this._calendar = new GregorianCalendar();
this._calendar.set(Calendar.YEAR, 2001);
System.out.println("definition 152 " +
" + this._calendar.get(Calendar.YEAR));
this._calendar.set(Calendar.MONTH, 12);
this._calendar.set(Calendar.DATE, 13);
this._calendar.set(Calendar.HOUR, 9);
this._calendar.set(Calendar.MINUTE, 34);
this._calendar.set(Calendar.SECOND, 45);
this._calendar.set(Calendar.MILLISECOND, 928);
System.out.println("definition 153 " +
" + this._calendar.get(Calendar.YEAR));
String dateform =
m = dateformatter.format(_calendar.getTime());
System.out.println("definition 155 " + dateform);
I get the output
definition 152 2001
definition 153 2002
definition 155 2002.01.03 12:11:14.928
How the year changes from 2001 to 2002 is a mystery.
However if I change the month to 6 then the behaviour
is different.
Any ideas as what is going on???????????
Months go from 0 to 11. Month 12 is actually month 0 (January) of the next year. See the documentation for the Calendar class at http://java.sun.com/j2se/1.3/docs/api/java/util/Calendar.html and the source for Calendar.java.
Also, you should use the named constants for the months instead of numbers, e.g. Calendar.DECEMBER.
Finally, the Calendar class does not attempt to resolve the various fields into milliseconds until one of the following methods is called: get(), getTime(), or getTimeInMillis(). This is explained in the Calendar API docs.
So, in summary, the reason the date is 2002/01 is because months are 0-based. The reason the date changed is because the milliseconds were recomputed when you called get(Calendar.YEAR).