Java interface extends Cloneable

Question

I don't understand why we can't do the following:

interface MyInterface extends Cloneable {}

class myClazz implements MyInterface {
    public Object clone() { return null; }
}

class test{
    public static void main(String[]a){
        MyInterface o = new myClazz();
        o.clone(); // IMPOSSIBLE
    }
}

But this will work fine

interface Misc{
    public void testM();
}

interface MyInterface extends Misc{}

class myClazz implements MyInterface {
    public void testM() {}
}

class test{
    public static void main(String[]a){
        MyInterface o = new myClazz();
        o.testM(); // OK
    }
}

What's happen with Cloneable?

Thanks,

Answer 1

The Cloneable interfaces doesn't have any methods.
It's just a marker interface which the base Object.clone method (which is protected) checks for.

If you want a clone method, you need to declare it yourself.