Difference between date in miliseconds and its Calendar representation

I have two functions which convert a date String to a date in milliseconds:

public static long convertYYYYMMDDtoLong(String date) throws ParseException {
    SimpleDateFormat f = new SimpleDateFormat("yyyy-mm-dd");
    Date d = f.parse(date);
    long milliseconds = d.getTime();
    return milliseconds;
}

If I run this function I get the following result:

long timeStamp = convertYYYYMMDDtoLong("2014-02-17");
System.out.println(timeStamp);

It prints: 

1389909720000

Now, if I run the following code:

Calendar cal = Calendar.getInstance();
cal.setTimeInMillis(timeStamp);
System.out.println(cal.getTime());

It prints out:

Fri Jan 17 00:02:00 IST 2014

Why is my date shifted by one month? What is wrong?

P.S: My problem is that I need to map the date, represented as long, to another third party API which accepts Calendar format only.

Jon Skeet
people
quotationmark

You're using mm, which is minutes, not months. You want yyyy-MM-dd as your format string.

It's not clear why you're not returning a Calendar directly from your method, mind you:

private static final TimeZone UTC = TimeZone.getTimeZone("Etc/UTC")

public static Calendar convertYYYYMMDDtoCalendar(String text) throws ParseException {        
    DateFormat format = new SimpleDateFormat("yyyy-MM-dd", Locale.US);
    format.setTimeZone(UTC);
    Calendar calendar = new GregorianCalendar(UTC);
    calendar.setDate(format.parse(text));
    return calendar;
}

(That's assuming you want a time zone of UTC... you'll need to decide that for yourself.)

people

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