// CalendarDate.java (modified CalendarDate class)
public class CalendarDate implements Comparable
{	
	// refer the textbook for the CalendarDate class
	
	private int month;
	private int day;
	private int year; // newly added variable

	// modified constructor
	public CalendarDate(int month, int day, int year)
	{
		this.month = month;
		this.day = day;
		this.year = year;
	}

	// modified method
	public int compareTo(CalendarDate other)
	{
		if(year != other.year)
		{
			return year - other.year;
		}
		if(month != other.month)
		{
			return month - other.month;
		}
		else
		{
			return day - other.day;
		}
	}

	// newly added method
	public int getYear()
	{
		return year;
	}
		
	public int getMonth()
	{
		return month;
	}

	public int getDay()
	{
		return day;
	}	

	// modified method
	public String toString()
	{
		return month + "/" + day + "/" + year;
	}
}

// CalendarDateDemo.java
import java.util.ArrayList;
import java.util.Collections;
public class CalendarDateDemo
{
	public static void main(String[] args)
	{
		CalendarDate cd1 = new CalendarDate(2, 2, 2001);
		CalendarDate cd2 = new CalendarDate(7, 18, 1995);
		CalendarDate cd3 = new CalendarDate(1, 30, 1995);
		CalendarDate cd4 = new CalendarDate(2, 1, 2001);

		ArrayList calendarDates = new ArrayList();
		calendarDates.add(cd1);
		calendarDates.add(cd2);
		calendarDates.add(cd3);
		calendarDates.add(cd4);

		System.out.println("Calendar dates in the list before soring: "
						+ calendarDates);

		Collections.sort(calendarDates);

		System.out.println("Calendar dates in the list after soring: "
						+ calendarDates);
	}
}

Output :

Calendar dates in the list before soring: [2/2/2001, 7/18/1995, 1/30/1995, 2/1/2001]
Calendar dates in the list after soring:  [1/30/1995, 7/18/1995, 2/1/2001, 2/2/2001]