程序代码：

import static java.lang.System.*;
public class no1 {
        static class abc{
         protected int shuzi=20;
        }
    public static void main(String[] args) {
        abc aaa=new abc();
        out.println("shuzi="+aaa.shuzi);
        aaa.shuzi=21;
        out.println("shuzi="+aaa.shuzi);
    }

}