Program: How to calculate difference between two dates in java?

package com.java2novice.date;

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

public class MyDateDifferenceExamples {

	public static void main(String a[]){
		
		String startDate = "22/02/2014 12:30:00";
		String endDate = "24/02/2014 12:30:00";
		
		/**
		 * SimpleDateFormat converts string format to date object
		 */
		SimpleDateFormat sdFormat = new SimpleDateFormat("dd/MM/yyyy HH:mm:ss");
		try {
			Date startDateObj = sdFormat.parse(startDate);
			Date endDateObj = sdFormat.parse(endDate);
			// startDateObj.getTime() method gives date in milli seconds format
			System.out.println("Time in milli seconds: "+startDateObj.getTime());
			
			// find time difference in milli seconds
			long timeDiff = endDateObj.getTime() - startDateObj.getTime();
			System.out.println("Time difference in Milli seconds: "+timeDiff);
			
			// time difference in seconds
			long secondsDiff = (timeDiff/1000);
			System.out.println("Time difference in seconds: "+secondsDiff);
			
			// time difference in minutes
			long minDiff = timeDiff/(1000*60);
			System.out.println("Time difference in minutes: "+minDiff);
			
			// time difference in minutes
			long hoursDiff = timeDiff/(1000*60*60);
			System.out.println("Time difference in hours: "+hoursDiff);
			
			// time difference in minutes
			long daysDiff = timeDiff/(1000*60*60*24);
			System.out.println("Time difference in days: "+daysDiff);
			
		} catch (ParseException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}

Time in milli seconds: 1393052400000
Time difference in Milli seconds: 172800000
Time difference in seconds: 172800
Time difference in minutes: 2880
Time difference in hours: 48
Time difference in days: 2