Re: Date/Calendar confusion

Lew <>
Thu, 6 Sep 2012 10:21:35 -0700 (PDT)
Ulrich Scholz wrote:

have a look at the function below (Java 5). The first result is 0 as exp=

ected. But why is the second one different?

private static void testDate() throws ParseException
        SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd'=


It's lenient by default.
"The default is lenient."

Check the docs when you have a question like this.

        TimeZone timeZone = TimeZone.getTimeZone("GMT");
        timeZone.setRawOffset(0); // get GMT time zone for sure


        Calendar calendar1 = Calendar.getInstance(timeZone, Locale.US);
        Date date1 = dateFormat.parse("1970-01-01T00:00:00.000");
        System.out.println(calendar1.getTimeInMillis()); // is 0
        Calendar calendar2 = Calendar.getInstance(timeZone, Locale.US);
        Date date2 = dateFormat.parse("0000-00-00T00:00:00.000");

What date is that, really?

        // adjust for the epoch 01.01.1970
        calendar2.set(Calendar.YEAR, calendar2.get(Calendar.YEAR) + 1970)=


        calendar2.set(Calendar.MONTH, calendar2.get(Calendar.MONTH) + 1);

By this time, 'get(Calendar.MONTH)' is probably not what you think.

        calendar2.set(Calendar.DAY_OF_MONTH, calendar2.get(Calendar.DAY_O=

F_MONTH) + 1);

" As a result of changing a calendar field using set(), other calendar fiel=
ds may also change, depending on the calendar field, the calendar field val=
ue, and the calendar system. In addition, get(f) will not necessarily retur=
n value set by the call to the set method after the calendar fields have be=
en recomputed. The specifics are determined by the concrete calendar class.=

        System.out.println(calendar2.getTimeInMillis()); // should be 0 b=

ut is -124335907200000


When you set the 'Calendar' to the invalid date, it readjusted its internal=
 values so those
'00' values were made into valid values.


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