Please explain this polymorphism twist to me.

Hi there,

I discovered a strange twist in polymorphism that leaves me in the
dark. If you can figure out what the following output will be, then
please explain to me why.

public class OverloadTest {

    public class Visitor {
    public void visit(Super s) {
        System.out.println("Visitor.visit(Super)");
    }

    public void visit(Sub s) {
        System.out.println("Visitor.visit(Sub)");
    }
    }

    public class Super {
    public void accept(Visitor visitor) {
        visitor.visit(this);
    }
    }

    public class Sub extends Super {
    }

    public static void main(String[] args) {
    OverloadTest o = new OverloadTest();
    Sub s = o.new Sub();
    s.accept(o.new Visitor());
    }
}

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"Visitor.visit(Super)"
That means, the call "visitor.visit(this);" in the type Super is
handled by "Visitor.visit(Super)" instead of "Visitor.visit(Sub)".
This occurs as especially strange to me because a look in the debugger
confirms that the actual (dynamic) type of "this" is Sub! In my
opinion, the call should therefore be dynamically handled by
"Visitor.visit(Sub)".

I hope I didn't confuse you with Super-Sub, now, and you can tell me
where I need to review the JLS to turn on my light again.

--
Cheers
Martin