【Java每日一题】20161221

20161220问题解析请点击今日问题下方的“【Java每日一题】20161221”查看

package Dec2016;

public class Ques1221 {

}

class Parent{
    public void test(){
        System.out.println("Parent test");
    }
}

class Sub extends Parent{
    public String test(){
        System.out.println("Sub test");
    }
}

今日问题：
请问主程序是否有编译错误？（点击以下“【Java每日一题】20161221”查看20161220问题解析）

题目原发布于公众号、简书：[url=http://mp.weixin.qq.com/s?__biz=MzI4ODEyMTgwMA==&mid=2650163312&idx=1&sn=8322e7f228fc3ec2aec39b44367ccee3&chksm=f3c1ded7c4b657c1b4a7290a049ad1daca367e2d66c012a9fadcacbfcb619bbfc5bf1dd09c21#rd]【Java每日一题】20161221[/url]，[url=http://www.jianshu.com/p/1ea8b0c4e08a]【Java每日一题】20161221 [/url]

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[img]https://img-blog.youkuaiyun.com/20161017115128961?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast[/img]

[img]http://upload-images.jianshu.io/upload_images/748537-fe59cc3e8df937fe.png?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240[/img]