why won't this compile; on Collection line? (math.geom2d, not matlab)

// Create and draw a circle
Circle2D circle1 = new Circle2D(80, 120, 40);
circle1.draw(g2);

// Create and draw a circle
Circle2D circle2 = new Circle2D(100, 120, 40);
circle2.draw(g2);

Collection<Point2D> intersects = circlesIntersections( circle1,circle2);
for (Point2D points:intersects)
    point.draw(g2,2,g2,2);