Java finding difference between times

Question

i have some problem while finding difference between times, if i try to find difference in todays time (say t1 = \"08:00:00\" and t2 = \"10:00:00\" then it is giving correct

Answer 1

Any date/time manipulation/calculation should be done though the use of well defined and tested APIs like Java 8's Time API or Joda Time

Java 8

public class TestTime {

    public static void main(String[] args) {
        // Because of the ability for the time to roll over to the next
        // day, we need the date component to make sense of it, for example
        // 24:00 is actually 00:00 of the next day ... joy
        LocalDateTime t1 = LocalTime.of(20, 00).atDate(LocalDate.now());
        LocalDateTime t2 = LocalTime.of(12, 00).atDate(LocalDate.now());
        LocalDateTime t3 = LocalTime.MIDNIGHT.atDate(LocalDate.now()).plusDays(1);

        if (t1.isAfter(t2)) {
            System.out.println("Before");
            Duration duration = Duration.between(t2, t3);
            System.out.println(format(duration));
        } else {
            System.out.println("After");
            Duration duration = Duration.between(t2, t1);
            System.out.println(format(duration));
        }
    }

    public static String format(Duration duration) {
        long hours = duration.toHours();
        duration = duration.minusHours(hours);

        return String.format("%02d hours %02d minutes", hours, duration.toMinutes());
    }

}

Which outputs

12 hours 00 minutes

The question I can't seem to answer in your code is why you did this s4 = s2+s3;, basically adding 12:00 to 24:00