Java Collision Detection and bounce- two circles collision and response

Collision detection between two circles and their response - Java source code - working

    public static void intersect(Ball a, Ball b) {
        //ref http://gamedev.stackexchange.com/questions/20516/ball-collisions-sticking-together
        double xDist, yDist;
        xDist = a.x - b.x;
        yDist = a.y - b.y;
        double distSquared = xDist * xDist + yDist * yDist;
        // Check the squared distances instead of the the distances, same
        // result, but avoids a square root.
        if (distSquared <= (a.radius + b.radius) * (a.radius + b.radius)) {
            double speedXocity = b.speedX - a.speedX;
            double speedYocity = b.speedY - a.speedY;
            double dotProduct = xDist * speedXocity + yDist * speedYocity;
            // Neat vector maths, used for checking if the objects moves towards
            // one another.
            if (dotProduct > 0) {
                double collisionScale = dotProduct / distSquared;
                double xCollision = xDist * collisionScale;
                double yCollision = yDist * collisionScale;
                // The Collision vector is the speed difference projected on the
                // Dist vector,
                // thus it is the component of the speed difference needed for
                // the collision.
                double combinedMass = a.getMass() + b.getMass();
                double collisionWeightA = 2 * b.getMass() / combinedMass;
                double collisionWeightB = 2 * a.getMass() / combinedMass;
                a.speedX += (collisionWeightA * xCollision);
                a.speedY += (collisionWeightA * yCollision);
                b.speedX -= (collisionWeightB * xCollision);
                b.speedY -= (collisionWeightB * yCollision);
            }
        }
    }