现有两种 OldPhone NewPhone； 两个类都有call() sendMessage() 方法(考虑向上抽取一个父类)?

package cn.zxj.com;public class Phone {public void call(){System.out.println("call");}public void sendMessage(){System.out.println("发短信");}}

package cn.zxj.com;public class OldPhone extends Phone{
}

package cn.zxj.com;public class NewPhone extends Phone{public void weixin(){System.out.println("liao weixin");}
}

package cn.zxj.com;public class Test {public static void main(String[] args) {Phone p = new NewPhone();p.call();p.sendMessage();//向下转型NewPhone nP = (NewPhone) p;nP.weixin();}
}