Write a program to show concept of Class in Java

Write a program to show concept of Class in Java

class box {

                        double width;

                        double height;

                        double depth;

}

class boxdemo {

                        public static void main (String arg[]) {

                                    box mybox1 = new box();

                                    double vol;

                                    //assign values to mybox1's instance variables

                                    mybox1.width=10;

                                    mybox1.height=20;

                                    mybox1.depth=15;

                       

                                    vol=mybox1.width * mybox1.height * mybox1.depth;

                                    System.out.print("Volume : "+vol);

                        }

            }