public class Vector2D { private float mX; private float mY; public Vector2D(float x, float y) { mX=x; mY=y; } public float getX() { return mX; } public float getY() { return mY; } public void add(Vector2D v) { mX+=v.mX; mY+=v.mY; } public static Vector2D add(Vector2D v1, Vector2D v2) { return new Vector2D(v1.getX()+v2.getX(), v1.getY()+v2.getY()); } }