My self-study inheritance and sub-class exercise
First of all, I'd change how the Point class functions because like David Harkness said, your Point class resembles that of a Line.  I would have it representing two values (x, y) and include functions that would make it easier to find the area of a shape.  Here's an example:

    public class Point {

        public float x;
        public float y;

        public Point(float x, float y) {
            this.x = x;
            this.y = y;
        }

        public static float distanceTo(Point from, Point to) {
            // Distance formula
            return Math.sqrt(Math.pow(to.x - to.y, 2) + Math.pow(from.x - from.y, 2));
        }


Using that point class, I could implement it into a Shape class to centralize a getArea() function.  To have different types of shapes, you could extend the Shape class from other classes and specify how many points each class or override the getArea() function.