摘要：
USB 接口 package com.ITheima._polymorphic_test; public interface USB { void connect(); void unconnect(); } View Code KeyBoard键盘类 package com.ITheima._po 阅读全文
摘要：
Animal类 package com.ITheima._polymorphic; public abstract class Animal { public String name="父类动物"; public abstract void run(); } View Code Dog类 packa 阅读全文