Question

I’m having an inexplicable problem with the Java Calendar class when I’m trying to compare to dates. I’m trying to compare to Calendars
and determine if their difference is > than 1 day, and do things bases on that difference or not. But it doesn’t work.

If I do this with the two dates:

    String currDate = aCurrentUTCCalendar.getTime().toString();
    String localDate = aLocalCalendar.getTime().toString();

I get these results:

    currDate  = "Thu Jan 06 05:58:00 MST 2010"
    localDate = "Tue Jan 05 00:02:00 MST 2010"

This is correct.

But if I do this:

    long curr = aCurrentUTCCalendar.getTime().getTime();
    long local = aLocalCalendar.getTime().getTime();

I get these results: ( in milliseconds since the epoch )

    curr  = -125566110120000 
    local =  1262674920000 

Since there is only about a 30 hour different between the two, the magnitudes are vastly different, not to mention that annoying negative
sign.

This causes problems if I do this:

long day = 60 * 60 * 24 * 1000; // 86400000 millis, one day

if( local - curr > day )
{
    // do something
}

What’s wrong? Why are the getTime().toString() calls correct, but the getTime().getTime() calls are vastly different?

I’m using jdk 1.6_06 on WinXP. I can’t upgrade the JDK for various reasons.

Answer 1

The answer was to use the JodaTime class. Thanks for the intro, it was way easier to get the results that I wanted instead of Java’s hard-to-use stuff.

I leave this as one of the oddities of those Java.Util.Date and Java.Util.Calendar classes.

Thanks for the help.