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));    }}

来源：https://www.cnblogs.com/YRSWBY2016/p/12021567.html