Time difference gives wrong value

Question

I want to get the difference between two time values in Java. Below is the code snippet for the same:

    DateFormat sdf = new SimpleDateFormat("hh:mm");
    Date date1 = sdf.parse("11:45");
    Date date2 = sdf.parse("12:00");
    System.out.println(""+(date2.getTime()-date1.getTime())/60000);

    date1 = sdf.parse("12:45");
    date2 = sdf.parse("13:00");
    System.out.println(""+(date2.getTime()-date1.getTime())/60000);

    date1 = sdf.parse("13:00");
    date2 = sdf.parse("13:15");
    System.out.println(""+(date2.getTime()-date1.getTime())/60000);

Output in all the three cases respectively: Output1:-705 Output2:735 Output3:15

I don't understand why it is taking wrong value as it should be 15 in all the three cases.

If you want to get the difference of time, I'd suggest "http://stackoverflow.com/questions/5351483/calculate-date-time-difference-in-java ". — TheRealVira, Oct 24 '16 at 10:08
You're not specifying AM or PM. `12:00` is midnight. `11:45` is nearly noon. — khelwood, Oct 24 '16 at 10:15

score 3 · Accepted Answer · edited Oct 24 '16 at 21:39

3

First and biggest error:

You use 12-hour-clock (symbol h), but symbol H would be fine.

Another more subtle error:

Using SimpleDateFormat is error-prone because it implicitly uses a time zone (and the result could be changed by Daylight Saving Time switch, see the case of Europe/London when it was on Summer time in year 1970 - your implicit default year).

Therefore I suggest to use a more modern API. For example the built-in java.time package (Tutorial) in Java SE 8 with its LocalTime and ChronoUnit classes.

ChronoUnit.MINUTES.between(LocalTime.parse("11:45"), LocalTime.parse("12:00"))

edited Oct 24 '16 at 21:39

Basil Bourque

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answered Oct 24 '16 at 10:10

Meno Hochschild

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Thanks a lot. You saved my day.. :) – Raushan Oct 24 '16 at 10:25
FYI… Much of the java.time functionality is back-ported to Java 6 & 7 in [*ThreeTen-Backport*](http://www.threeten.org/threetenbp/). Further adapted for Android in the [*ThreeTenABP*](https://github.com/JakeWharton/ThreeTenABP) project. – Basil Bourque Oct 24 '16 at 21:41

Time difference gives wrong value

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