Comparing And Cloning Objects?

I'm working on a program with the following instructions: Write a class named Octagon that extends GeometricObject and implements the Comparable and Cloneable interfaces. Assume that all 8 sides of the octagon are of equal size. The area can be computed using the following formula

area = (2 + 4/square root of 2) * side * side

Write a program (driver) to read in a series of values from a file, display the area and perimeter, create a clone and compare the object and its clone (based on the area). In addition, your program should compare the current object (just read in) with the first object read in. The program ends when a negative number is read from the file.

My GeometricObject abstract class:

public abstract class GeometricObject {
public abstract double getArea();
public abstract double getPerimeter();
}

My Octagon Class:

public class Octagon extends GeometricObject implements Comparable<Octagon> {
private double side = 1.0;
protected native Object clone() throws CloneNotSupportedException;
public Octagon() {
}
public Octagon(double side) {
super();

[code]....

As you can tell, I've still got a long way to go in the tester class but this is where I'm running into some difficulties.

You'll notice that in the return statement of the toString method in the Octagon class, I put a ? after the "Clone Compare:" portion of the code, what should go here. I've never worked with either the Comparable or Cloneable interfaces before.

How I should create my objects in a way that would give the following sample output.

Object 1: Area: 120.71
Perimeter: 40.0
Clone Compare: Equal
First Compare: Equal

Object 2: Area: 271.60
Perimeter: 60.0
Clone Compare: Equal
First Compare: First is smaller