Java에서 날짜 및 시간 차이를 효율적으로 계산하려면 어떻게 해야 합니까?

String dateStart = "11/03/14 09:29:58";
String dateStop = "11/03/14 09:33:43";

SimpleDateFormat format = new SimpleDateFormat("yy/MM/dd HH:mm:ss");

Date d1 = null;
Date d2 = null;
try {
    d1 = format.parse(dateStart);
    d2 = format.parse(dateStop);
} catch (ParseException e) {
    e.printStackTrace();
}

// Get msec from each, and subtract.
long diff = d2.getTime() - d1.getTime();
long diffSeconds = diff / 1000;
long diffMinutes = diff / (60 * 1000);
long diffHours = diff / (60 * 60 * 1000);

System.out.println("Time in seconds: " + diffSeconds + " seconds.");
System.out.println("Time in minutes: " + diffMinutes + " minutes.");
System.out.println("Time in hours: " + diffHours + " hours.");

long diffSeconds = TimeUnit.MILLISECONDS.toSeconds(diff);