ShoppingBill.java

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

class Product {
    // properties
    private String pname;
    private int qty;
    private double price;
    private double totalPrice;

    // constructor
    Product(String pname, int qty,
            double price, double totalPrice) {
        this.pname = pname;
        this.qty = qty;
        this.price = price;
        this.totalPrice = totalPrice;
    }

    // getter methods
    public String getPname() {
        return pname;
    }

    public int getQty() {
        return qty;
    }

    public double getPrice() {
        return price;
    }

    public double getTotalPrice() {
        return totalPrice;
    }

    // displayFormat
    public static void displayFormat() {
        System.out.print(
                "\nName      Quantity    Price   Total Price\n");
    }

    // display
    public void display() {
        System.out.format("%-9s %8d %10.2f %10.2f\n",
                pname, qty, price, totalPrice);
    }
}

public class ShoppingBill {
    public static void main(String[] args) {

        // variables
        String productName = null;
        int quantity = 0;
        double price = 0.0;
        double totalPrice = 0.0;
        double overAllPrice = 0.0;
        char choice = '\0';

        // create Scanner class object
        Scanner scan = new Scanner(System.in);

        List<Product> product = new ArrayList<Product>();

        do {
            // read input values
            System.out.println("Enter product details,");
            System.out.print("Name: ");
            productName = scan.nextLine();
            System.out.print("Quantity: ");
            quantity = scan.nextInt();
            System.out.print("Price (per item): ");
            price = scan.nextDouble();

            // calculate total price for that product
            totalPrice = price * quantity;

            // calculate overall price
            overAllPrice += totalPrice;

            // create Product class object and add it to the list
            product.add(new Product(
                    productName, quantity, price, totalPrice));

            // ask for continue?
            System.out.print("Want to add more item? (y or n): ");
            choice = scan.next().charAt(0);

            // read remaining characters, don't store (no use)
            scan.nextLine();
        } while (choice == 'y' || choice == 'Y');

        // display all product with its properties
        Product.displayFormat();
        for (Product p : product) {
            p.display();
        }

        // overall price
        System.out.println("\nTotal Price = " + overAllPrice);

        // close Scanner
        scan.close();
    }

}