In Java, how do I get the difference in seconds between 2 dates?

The Java class library has a class named DateTime. DateTime has this method:

int daysBetween(DateTime other)

which returns the number of days between this and the parameter. It doesn't have a method

int secondsBetween(DateTime other)

which I happen to need. Is there a class which is similar to DateTime but has such a method?

Not familiar with DateTime...

If you have two Dates you can call getTime on them to get millseconds, get the diff and divide by 1000. For example

Date d1 = ...;
Date d2 = ...;
long seconds = (d2.getTime()-d1.getTime())/1000;

If you have Calendar objects you can call

c.getTimeInMillis()

and do the same

I should like to provide the modern answer. The other answers were fine when this question was asked, but time moves on. Today I recommend you use java.time, the modern Java date and time API.

    ZonedDateTime aDateTime = ZonedDateTime.of(2017, 12, 8, 19, 25, 48, 991000000, ZoneId.of("Europe/Sarajevo"));
    ZonedDateTime otherDateTime = ZonedDateTime.of(2017, 12, 8, 20, 10, 38, 238000000, ZoneId.of("Europe/Sarajevo"));

    long diff = ChronoUnit.SECONDS.between(aDateTime, otherDateTime);
    System.out.println("Difference: " + diff + " seconds");

This prints:

Difference: 2689 seconds

ChronoUnit.SECONDS.between() works with two ZonedDateTime objects or two OffsetDateTimes, two LocalDateTimes, etc.

If you need anything else than just the seconds, you should consider using the Duration class:

    Duration dur = Duration.between(aDateTime, otherDateTime);
    System.out.println("Duration: " + dur);
    System.out.println("Difference: " + dur.getSeconds() + " seconds");

This prints:

Duration: PT44M49.247S
Difference: 2689 seconds

The former of the two lines prints the duration in ISO 8601 format, the output means a duration of 44 minutes and 49.247 seconds.

Why java.time?

The Date class used in several of the other answers is now long outdated. Joda-Time also used in a couple (and possibly in the question) is now in maintenance mode, no major enhancements are planned, and the developers officially recommend migrating to java.time, also known as JSR-310.

Question: Can I use the modern API with my Java version?

If using at least Java 6, you can.

• In Java 8 and later the new API comes built-in.
• In Java 6 and 7 get the ThreeTen Backport, the backport of the new classes (ThreeTen for JSR 310).
• On Android, use the Android edition of ThreeTen Backport. It’s called ThreeTenABP, and there’s a thorough explanation in this question: How to use ThreeTenABP in Android Project.

You should do

org.joda.time.Seconds.secondBetween(date1, date2)

That should do it:

Date a = ...;
Date b = ...;

Math.abs(a.getTime()-b.getTime())/1000;

Here the relevant documentation: Date.getTime(). Be aware that this will only work for dates after January 1, 1970, 00:00:00 GMT

There is no such class as DateTime in the standard Java SE API. Although there is one in joda-time, even that does not have a daysBetween method.

Using the standard Java API, the easiest way to get seconds between two java.util.Date objects would be to subtract their timestamps and divide by 1000:

int secondsBetween = (date1.getTime() - date2.getTime()) / 1000;