Java calculate days in year, or between two dates

Question

Is there a method in any native Java class to calculate how many days were/will be in a specific year? As in, was it a Leap year (366 days) or a normal year (365 days)?

Answer 1

You can use the TimeUnit class. For your specific needs this should do:

public static int daysBetween(Date a, Date b) {
    final long dMs = a.getTime() - b.getTime();
    return TimeUnit.DAYS.convert(dMs, TimeUnit.MILLISECONDS);
}

Honestly, I don't see where leap years play any role in this calculation, though. Maybe I missed some aspect of your question?

Edit: Stupid me, the leap years magic happens in the Date.getTime(). Anyway, you don't have to deal with it this way.