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Groups > comp.lang.java.programmer > #18577

Re: Date/Calendar confusion

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In article <3a69eb4a-f3c0-4b56-9a67-6833ccb2a1c8@googlegroups.com>,
 Ulrich Scholz <d7@thispla.net> wrote:

> calendar2.set(Calendar.YEAR, calendar2.get(Calendar.YEAR) + 1970);
> calendar2.set(Calendar.MONTH, calendar2.get(Calendar.MONTH) + 1);
> calendar2.set(Calendar.DAY_OF_MONTH,
>      calendar2.get(Calendar.DAY_OF_MONTH) + 1);

Note that Calendar.JANUARY is not 1. Use clear() to set some or all 
fields to a known (undefined, !isSet()) state.

public static void main(String[] args) {
    TimeZone timeZone = TimeZone.getTimeZone("GMT");
    SimpleDateFormat f = new SimpleDateFormat(
        "yyyy-MMM-dd HH:mm:ss.SSS Z");

    Calendar calendar1 = Calendar.getInstance(timeZone);
    System.out.println(f.format(calendar1.getTime()));
    calendar1.clear();
    System.out.println(calendar1.getTimeInMillis()); // 0

    Calendar calendar2 = Calendar.getInstance(timeZone);
    System.out.println(f.format(calendar2.getTime()));
    calendar2.set(Calendar.YEAR, 1970);
    calendar2.set(Calendar.MONTH, Calendar.JANUARY);
    calendar2.set(Calendar.DAY_OF_MONTH, 1);
    calendar2.clear(Calendar.HOUR);
    calendar2.clear(Calendar.MINUTE);
    calendar2.clear(Calendar.SECOND);
    calendar2.clear(Calendar.MILLISECOND);
    System.out.println(calendar2.getTimeInMillis()); // 0
}

-- 
John B. Matthews
trashgod at gmail dot com
<http://sites.google.com/site/drjohnbmatthews>

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Thread

Date/Calendar confusion Ulrich Scholz <d7@thispla.net> - 2012-09-06 01:03 -0700
  Re: Date/Calendar confusion nogales <nogales.manuel@gmail.com> - 2012-09-06 02:29 -0700
  Re: Date/Calendar confusion Lew <lewbloch@gmail.com> - 2012-09-06 10:21 -0700
  Re: Date/Calendar confusion "John B. Matthews" <nospam@nospam.invalid> - 2012-09-06 20:53 -0400
    Re: Date/Calendar confusion Lew <lewbloch@gmail.com> - 2012-09-07 11:01 -0700
      Re: Date/Calendar confusion "John B. Matthews" <nospam@nospam.invalid> - 2012-09-07 21:02 -0400
        Re: Date/Calendar confusion Lew <lewbloch@gmail.com> - 2012-09-07 18:44 -0700
          Re: Date/Calendar confusion "John B. Matthews" <nospam@nospam.invalid> - 2012-09-08 09:12 -0400
            Re: Date/Calendar confusion Lew <lewbloch@gmail.com> - 2012-09-08 16:51 -0700

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