Java date counting

Question

I need to calculate the number of days passed between 2 dates using java.util.Date, java.util.Calendar and java.text.SimpleDateFormat. I'm breaking my brain, how could I accomplish that?

No guys I've done half of the task and I doubt that it would be effective to subtract current date from the date given using Calendar and than iterate until the year == 0 adding to the sum 365/366 days... — OneMoreVladimir, May 08 '12 at 21:07
No indeed would anyone help after the previous two gentlemen wrapped the problem into the 'homework' paper? — OneMoreVladimir, May 08 '12 at 21:12
I've used it and the solution was quite elegant, but I need to use only standard API. — OneMoreVladimir, May 08 '12 at 21:16
java.util.Date is in UTS so a simple math like this will give you what you want int daysBetween = (endDate.getTime() - startDate.getTime())/totalMillisecondsInADay — Aravind Yarram, May 08 '12 at 21:22
Check this question : http://stackoverflow.com/questions/3299972/difference-in-days-between-two-dates-in-java — StepTNT, May 08 '12 at 21:23

score 1 · Accepted Answer · answered May 23 '12 at 12:49

It seems like an interview question, similar was asked to me in an interview 2 months back.

Well, here is another hint: You have two dates. Java gives you time in millis for each date. Say t1 and t2.

Without loss of generality we can assume t1>t2. now t = t1-t2

divide t by 86400 * 1000 ( number of milliseconds in a day) and that is your answer :)

Java date counting

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