大神帮我看看~我是新手。

class MethodExample
    {
        private int x;     
        private static int y;   
         void f()
            {      
                x=20;  
                System.out.println("x="+x+",y="+y);
                g(30);   
             }
    static void g(int a)
    {   
        y=a;
        printY();
     }
        static void  printY()
        {   
            System.out.println("y="+y);
        }
}
    public class Main {
    static String mystring="hello";

    public static void main(String args[])  
 {
    System.out.println(mystring);
    new MethodExample.f();      
    new MethodExample.g(60);         
 }
}

只修改Main里面的内容，怎么修改？