Java 多态 代码

Java中多态的实现方式：接口实现，继承父类进行方法重写，同一个类中进行方法重载。

看代码：

package com.company;

public class Main {

    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));
    }

}

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 {
}

http://www.cnblogs.com/jack204/archive/2012/10/29/2745150.html