Comparing dates...

[Daniel Harris]

If I subtract a date that is recent (a few weeks) from today's date, I get a negative number returned.

        Date now = new Date();
        GregorianCalendar entryDate = new GregorianCalendar(year, month, day, hour, minute, second);
        long then = now.getTime() - entryDate.getTimeInMillis();

getTimeInMillis() returns a negative number if the date of entryDate is within the past few weeks.

Can anybody tell me why?

[Rob Spoor]

It should only return a negative value if the date is before 00:00:00 GMT on January 1st 1970. This date time is also called the epoch - see java.util.Calendar for more info. This point of time is represented as 0 in Java's calendars and dates (among others; PHP also uses it). Any time before that is always negative.

That still does not explain why a few weeks ago is negative. Can you tell us what values you are using when creating the GregorianCalendar?

[Daniel Harris]

Thanks or replying!

Heres an example that returns a negative number...

Date now = new Date();
        
GregorianCalendar entryDate = new GregorianCalendar(2009, 2, 23, 20, 20, 31);
        
//GregorianCalendar entryDate = new GregorianCalendar(year, month, day, hour, minute, second);

long then = now.getTime() - entryDate.getTimeInMillis();

then == a negative number.

Like I said though... it only does this if the past date is within a few weeks.

[Paul Clapham]

But that's not a "past date". It's March 23 of this year and we haven't got there yet.

[Daniel Harris]

Paul Clapham wrote:But that's not a "past date". It's March 23 of this year and we haven't got there yet.

Ahhh.... I see says the greenhorn! Thanks!

[Rob Spoor]

This is exactly why you can better use the Calendar constants like Calendar.FEBRUARY.

[Daniel Harris]

Rob Prime wrote:This is exactly why you can better use the Calendar constants like Calendar.FEBRUARY.

The calendar is created with variables... The constants dont apply here. Thanks for the advice though!