How to calculate date and time difference in java

Converts Date in milliseconds (ms) and calculate the differences between two dates, with following rules :

1000 milliseconds = 1 second
60 seconds = 1 minute
60 minutes = 1 hour
24 hours = 1 day

DateDifferentExample.java

package com.blogspot.s2ptech.date;

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

public class DateDifferentExample {

public static void main(String[] args) {

String dateStart = "01/14/2012 09:29:58";
String dateStop = "01/15/2012 10:31:48";

//HH converts hour in 24 hours format (0-23), day calculation
SimpleDateFormat format = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss");

Date d1 = null;
Date d2 = null;

try {
d1 = format.parse(dateStart);
d2 = format.parse(dateStop);

//in milliseconds
long diff = d2.getTime() - d1.getTime();

long diffSeconds = diff / 1000 % 60;
long diffMinutes = diff / (60 * 1000) % 60;
long diffHours = diff / (60 * 60 * 1000) % 24;
long diffDays = diff / (24 * 60 * 60 * 1000);

System.out.print(diffDays + " days, ");
System.out.print(diffHours + " hours, ");
System.out.print(diffMinutes + " minutes, ");
System.out.print(diffSeconds + " seconds.");

} catch (Exception e) {
e.printStackTrace();
}

}

}

Result

1 days, 1 hours, 1 minutes, 50 seconds.