public class Test {
    public static void main(String[] s) {
        A a = new B();
        a.b();
    }
}

class A {
    void a() {
        System.out.println("A-a");
    }
    
    void b() {
        System.out.println("A-b");
        a();
    }
}

class B extends A {
    void a() {
        System.out.println("B-a");
    }
    
    void b() {
        System.out.println("B-b");
        super.b();
    }
}