Cannot find symbol in java when i use object

when I execute it in command prompt, it gives error to height that cannot find symbol

class vol {
       int height;
       int width;
       int length;
}

class box {
      public static void main(String args[]) {
         vol mybox = new vol(); // mybox is created as a object
         mybox.height = 10;
         System.out.println(height);
      }
}

Problem is with System.out.println(height); line. It should be System.out.println(mybox.height);

class Vol {          
    int height;
    int width;
    int length;
}

class Box {
    public static void main(String args[]) {
        Vol mybox = new Vol();             //mybox is created as a object
        mybox.height = 10;
        System.out.println(mybox.height);
    }
}

Try this one.