Decrement a date in Java

Question

I want to get the previous day (24 hours) from the current time.

e.g if current time is Date currentTime = new Date();

2011-04-25 12:

Answer 1

24 hours and 1 day are not the same thing. But you do both using Calendar:

Calendar c = Calendar.getInstance();
c.setTime(new Date());
c.add(Calendar.DATE, -1);
Date d = c.getTime();

If you are going back 24 hours, you would use Calendar.HOUR_OF_DAY