多态

/*
多态的经典例子，要多多研究一下
 */

class A {
    public String show(D obj) {
        return ("A and D");
    }

    public String show(A obj) {
        return ("A and A");
    }
}

class B extends A {
    public String show(B obj) {
        return ("B and B");
    }

    public String show(A obj) {
        return ("B and A");
    }
}

class C extends B {
}

class D extends B {
}
class DynamicTest {
    public static void main(String[] args) {
        A a1 = new A();
        A a2 = new B();

        B b = new B();
        C c = new C();
        D d = new D();
        System.out.println(a1.show(b));
        System.out.println(a1.show(c));
        System.out.println(a1.show(d));

        System.out.println(a2.show(b));
        System.out.println(a2.show(c));
        System.out.println(a2.show(d));


        System.out.println(b.show(b));
        System.out.println(b.show(c));
        System.out.println(b.show(d));
    }

}