Java cloning abstract objects

Question

I\'m wondering if there is any way to do the following. I have an abstract class, Shape, and all its different subclasses and I want to override the clone metho

Answer 1

You can't create deep clone of abstract class because they can't be instantiated. All you can do is shallow cloning by using Object.clone() or returning this

@Override
public Object clone() throws CloneNotSupportedException {
    return super.clone();
}

or

@Override
public Object clone() throws CloneNotSupportedException {
    return this;
}

An abstract class can act as a reference, and it cannot have an instance so shallow cloning works in this case

OR

As a better approach, you can declare clone() as abstract and ask child class to define it, something like this

abstract class Shape {

    private String str;

    public Shape(String str) {
        this.str = str;
    }

    public abstract Shape clone();

    public String toString() {
        return str;
    }
}

class Circle extends Shape {

    public Circle(String str) {
        super(str);
    }

    @Override
    public Shape clone() {
        return new Circle("circle");
    }

}