Class equality in JAVA [closed]

I want to equalize two object like this:

    public abstract class Shape{...} // There is an abstract shape class

    public class Circle extends Shape {
        int radius;
        ...
    }

    public class ColoredCircle extends Circle{
        Color color;
        public ColoredClass(Circle circle) {
            this = circle;                  // This line has a problem. 
            this.color = Color.RED;
        }
    }

How can i copy all fields to sub-class with current values?