Basic OOP Question

public class CreateObjectDemo {
    public static void main(String[] args) {

        // create a point object and two rectangle objects
        Point origin_one = new Point(23, 94);
        Rectangle rect_one = new Rectangle(origin_one, 100, 200);
        Rectangle rect_two = new Rectangle(50, 100);

        // display rect_one's width, height, and area
        System.out.println("Width of rect_one: " + rect_one.width);
        System.out.println("Height of rect_one: " + rect_one.height);
        System.out.println("Area of rect_one: " + rect_one.area());

        // set rect_two's position
        rect_two.origin = origin_one;

        // display rect_two's position
        System.out.println("X Position of rect_two: " + rect_two.origin.x);
        System.out.println("Y Position of rect_two: " + rect_two.origin.y);

        // move rect_two and display its new position
        rect_two.move(40, 72);
        System.out.println("X Position of rect_two: " + rect_two.origin.x);
        System.out.println("Y Position of rect_two: " + rect_two.origin.y);
    }
}

public class Point {
    public int x = 0;
    public int y = 0;
    // a constructor!
    public Point(int x, int y) {
	this.x = x;
	this.y = y;
    }
}

public class Rectangle {
    public int width = 0;
    public int height = 0;
    public Point origin;

    // four constructors
    public Rectangle() {
	origin = new Point(0, 0);
    }
    public Rectangle(Point p) {
	origin = p;
    }
    public Rectangle(int w, int h) {
	this(new Point(0, 0), w, h);
    }
    public Rectangle(Point p, int w, int h) {
	origin = p;
	width = w;
	height = h;
    }

    // a method for moving the rectangle
    public void move(int x, int y) {
	origin.x = x;
	origin.y = y;
    }

    // a method for computing the area of the rectangle
    public int area() {
	return width * height;
    }
}