Implementing Comparable interface? Help please.

Question

Why am I getting the following error?
Exception in thread "main" java.lang.ClassCastException: java.lang.Double cannot be cast to chapter10.RectangleJust look at the test class and ComparableRectangle class if you can find the bug.
Here are the 3 of 4 classes:
package chapter10;
public class TestComparableRectangle {
    public static void main (String[] args) {
        ComparableRectangle area1 = new ComparableRectangle(3.0, 6.0);
        ComparableRectangle area2 = new ComparableRectangle(5.0, 4.0);
        int result = area1.compareTo(area2.getArea());
        if (result == -1)
            System.out.println("area1 " + area1.getArea() + " < "
                    + area2.getArea() + " area2.");
        else if (result == 0)
            System.out.println("area1 " + area1.getArea() + " = "
                    + area2.getArea() + " area2.");
        else
            System.out.println("area1 " + area1.getArea() + " > "
                    + area2.getArea() + " area2.");
package chapter10;
public class ComparableRectangle extends Rectangle implements Comparable{
    /** Construct a ComprableRectangle with specified properties */
    public ComparableRectangle(double width, double height) {
        super(width, height);
    /*  Implement the compareTo method defined in Comparable */
    @Override
    public int compareTo(Object x) {
        if (getArea() > ((Rectangle)x).getArea())
            return 1;
        else if (getArea() < ((Rectangle)x).getArea())
            return -1;
        else
            return 0;
package chapter10;
public class Rectangle extends GeometricObject {
    private double width;
    private double height;
    public Rectangle(){
    public Rectangle (double width, double height) {
        this.width = width;
        this.height = height;
    // Return width
    public double getWidth () {
        return width;
    // Set a new width
    public void setWidth (double width) {
        this.width = width;
    // Return height
    public double getHeight () {
        return height;
    public void setHeight (double height) {
        this.height = height;
    // Return area
    public double getArea () {
        return width * height;
    //Return parimeter
    public double getPerimeter() {
        return 2 * (width + height);
}Thanks in advance.

Answer 1

Thanks a lot friend. It has been a week I've been trying to find the problem. In fact I was adding/casting the left side, but never tried the right side.
This is what I changed it and it worked.
int result = area1.compareTo(area2);Thank you.