Calculate days difference between two dates?

import java.util.Calendar;

public class DateDifferentExample
{
public static void main(String[] args)
{
// Creates two calendars instances
Calendar cal1 = Calendar.getInstance();
Calendar cal2 = Calendar.getInstance();

// Set the date for both of the calendar instance
cal1.set(2006, 12, 30);
cal2.set(2007, 05, 03);

// Get the represented date in milliseconds
long milis1 = cal1.getTimeInMillis();
long milis2 = cal2.getTimeInMillis();

// Calculate difference in milliseconds
long diff = milis2 - milis1;

// Calculate difference in seconds
long diffSeconds = diff / 1000;

// Calculate difference in minutes
long diffMinutes = diff / (60 * 1000);

// Calculate difference in hours
long diffHours = diff / (60 * 60 * 1000);

// Calculate difference in days
long diffDays = diff / (24 * 60 * 60 * 1000);

System.out.println("In milliseconds: " + diff + " milliseconds.");
System.out.println("In seconds: " + diffSeconds + " seconds.");
System.out.println("In minutes: " + diffMinutes + " minutes.");
System.out.println("In hours: " + diffHours + " hours.");
System.out.println("In days: " + diffDays + " days.");
}
}