How to get number of days between two calendar instance?

Question

I want to find the difference between two Calendar objects in number of days if there is date change like If clock ticked from 23:59-0:00 there should be a day

Answer 1

I have the similar (not exact same) approach given above by https://stackoverflow.com/a/31800947/3845798.

And have written test cases around the api, for me it failed if I passed 8th march 2017 - as the start date and 8th apr 2017 as the end date.

There are few dates where you will see the difference by 1day. Therefore, I have kind of made some small changes to my api and my current api now looks something like this

   public long getDays(long currentTime, long endDateTime) {

Calendar endDateCalendar;
Calendar currentDayCalendar;


//expiration day
endDateCalendar = Calendar.getInstance(TimeZone.getTimeZone("EST"));
endDateCalendar.setTimeInMillis(endDateTime);
endDateCalendar.set(Calendar.MILLISECOND, 0);
endDateCalendar.set(Calendar.MINUTE, 0);
endDateCalendar.set(Calendar.HOUR, 0);
endDateCalendar.set(Calendar.HOUR_OF_DAY, 0);

//current day
currentDayCalendar = Calendar.getInstance(TimeZone.getTimeZone("EST"));
currentDayCalendar.setTimeInMillis(currentTime);
currentDayCalendar.set(Calendar.MILLISECOND, 0);
currentDayCalendar.set(Calendar.MINUTE, 0);
currentDayCalendar.set(Calendar.HOUR,0);
currentDayCalendar.set(Calendar.HOUR_OF_DAY, 0);


long remainingDays = (long)Math.ceil((float) (endDateCalendar.getTimeInMillis() - currentDayCalendar.getTimeInMillis()) / (24 * 60 * 60 * 1000));

return remainingDays;}

I am not using TimeUnit.MILLISECONDS.toDays that were causing me some issues.