brute force

    public BruteCollinearPoints(Point[] points){
        if (points == null)
            throw new NullPointerException();

        for (int p1 = 0; p1 < points.length; p1++){
            for (int p2 = 0; p2 < points.length; p2++){
                for (int p3 = 0; p3 < points.length; p3++){
                    for (int p4 = 0; p4 < points.length; p4++){
                        if (p1 != p2 && p1 != p3 && p1 != p4 && p2 != p3 && p2 != p4 && p3 != p4){

                        }
                    }
                }
            }

        }
    }