Difference of two Joda LocalDateTimes

I found a workaround by using following steps:

1. Take two LocalDateTime objects as Start and End
2. Convert both of them to Instant object such as start.toInstant(ZoneOffset.UTC);
3. Calculate the Duration using Duration.between(instant t1, instant t2)
4. Convert it into nanoseconds or milliseconds or seconds using various conversion methods. Nanoseconds can be calculated as Duration.toNanos()

I have provided a full example below.

public long getDuration(LocalDateTime start, LocalDateTime end) {

    //convert the LocalDateTime Object to an Instant 
    Instant startInstant = start.toInstant(ZoneOffset.UTC);         
    Instant endInstant   =   end.toInstant(ZoneOffset.UTC);

    //difference between two Instants is calculated
    //convert to nano seconds or milliseconds 
    long duration=Duration.between(startInstant, endInstant).toNanos();

    return duration;
}

Duration is better for some cases. You can get a "timezone-independent" duration for use with LocalDateTimes (in local time line) by this trick:

public static Duration getLocalDuration(LocalDateTime start, LocalDateTime end) {
    return new Duration(start.toDateTime(DateTimeZone.UTC), end.toDateTime(DateTimeZone.UTC));
}

You can use org.joda.time.Period class for this - in particular the fieldDifference method.

Example:

LocalDateTime endOfMonth = now.dayOfMonth().withMaximumValue();
LocalDateTime firstOfMonth = now.dayOfMonth().withMinimumValue();
Period period = Period.fieldDifference(firstOfMonth, endOfMonth)