langiole

public class Blue implements DrawAPI {
    @Override
    public void draw() {
        System.out.print("blue");
    }
}

langiole

public class Red implements DrawAPI {
    @Override
    public void draw() {
        System.out.print("red");
    }
}

langiole

public interface DrawAPI {
    public void draw();
}

langiole

public abstract class Shape {
    protected DrawAPI drawAPI;

    protected Shape(DrawAPI drawAPI){
        this.drawAPI = drawAPI;
    }
    public abstract void draw();
}