Java 2D Vector Class Implementation

vector2d.java

class Vector2D
{
    public double vX;
    public double vY;
    
    public static int count = 0;
    
    public Vector2D() {
        this.vX = this.vY = 1.0;
        count++;
    }
    
    public Vector2D(double x, double y)
    {
        this.vX = x;
        this.vY = y;
        count++;
    }
    
    public Vector2D(Vector2D source)
    {
        this.vX = source.vX;
        this.vY = source.vY;
        count++;
    }
    
    public void print()
    {
        System.out.printf("(%.2f, %.2f)\n", this.vX, this.vY);
    }
    
    public double length()
    {
        return Math.sqrt(Math.pow(this.vX, 2) + Math.pow(this.vY, 2));
    }
    
    public void add(Vector2D vector)
    {
        this.vX += vector.vX;
        this.vY += vector.vY;
    }
    
    public void sub(Vector2D vector)
    {
        this.vX -= vector.vX;
        this.vY -= vector.vY;
    }
    
    public void scale(double scaleFactor)
    {
        this.vX *= scaleFactor;
        this.vY *= scaleFactor;
    }
    
    public void normalized()
    {
        double length = this.length();
        this.vX /= length;
        this.vY /= length;
    }
    
    public double dotProduct(Vector2D vector)
    {
        return this.vX * vector.vX + this.vY * vector.vY;
    }
}