Collections.sort(points, new Comparator<Point>() {
              public int compare(Point a, Point b) {
                  if(a.getX() > b.getX()) {
                      return 1;
                  }else if(a.getX() < b.getX()) {
                      return -1;
                  }else {
                      return 0;
                  }
              }
          });