Unexpected difference in dates parsed using yyyy-MM-dd hh:mm:ss format

Question

I\'ve run the below java code to get time difference.

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.         


        

Answer 1

This is the problem:

new SimpleDateFormat("yyyy-MM-dd hh:mm:ss")

The hh here means "12 hour hour-of-day" so 12 means midnight unless there's something to indicate that it's meant to be 12 PM. Your value of 13 only works because the parser is in a lenient mode. You want:

new SimpleDateFormat("yyyy-MM-dd HH:mm:ss")

I'd also strongly advise you to use Joda Time for this task anyway, as it makes it a lot simpler.

Answer 2

Changing the SimpleDateFormat pattern to yyyy-MM-dd HH:mm:ss fixes the issues.

This happens because in the yyyy-MM-dd hh:mm:ss case, 12 is evaluated as 0.