Java Program

                             Product Calculation 

import java.text.DecimalFormat;

class ProductExcludingTax

 {

    private String productName;

    private int quantity;

    private double price;

    private double taxRate;

    public ProductExcludingTax(String productName, int quantity, double price, double taxRate)

 {

        this.productName = productName;

        this.quantity = quantity;

        this.price = price;

        this.taxRate = taxRate;

    }

    public double calculateTotalAmount()

 {

        double totalAmount = quantity * price;

        double taxAmount = totalAmount * taxRate;

        return totalAmount + taxAmount;

    }

    public void display()

 {

        DecimalFormat df = new DecimalFormat("#.##");

        double totalAmount = calculateTotalAmount();

        System.out.println("Product name: " + productName);

        System.out.println("Quantity: " + quantity);

        System.out.println("Price per unit: $" + df.format(price));

        System.out.println("Tax rate: " + (taxRate * 100) + "%");

        System.out.println("Total amount (including tax): $" + df.format(totalAmount));

    }

}

class ProductIncludingTax

 {

    private String productName;

    private int quantity;

    private double originalPrice;

    private double taxAmount;

    private double taxRate;

    public ProductIncludingTax(String productName, int quantity, double originalPrice, double taxRate)

 {

        this.productName = productName;

        this.quantity = quantity;

        this.originalPrice = originalPrice;

        this.taxRate = taxRate;

        this.taxAmount = originalPrice * taxRate;

    }

    public void display()

 {

        DecimalFormat df = new DecimalFormat("#.##");

        System.out.println("Product name: " + productName);

        System.out.println("Quantity: " + quantity);

        System.out.println("Tax included price per unit: $" + df.format(originalPrice));

        System.out.println("Tax rate: " + (taxRate * 100) + "%");

        System.out.println("Tax amount: $" + df.format(taxAmount));

        System.out.println("Original price (excluding tax): $" + df.format(originalPrice - taxAmount));

    }

}

public class Main

 {

    public static void main(String[] args)

 {

        ProductExcludingTax product1 = new ProductExcludingTax("Book", 2, 25.0, 0.08);

        product1.display();

        System.out.println();

        ProductIncludingTax product2 = new ProductIncludingTax("Laptop", 1, 1500.0, 0.10); 

        product2.display();

    }

}

Output:

Product name: Book

Quantity: 2

Price per unit: $25.0

Tax rate: 8.0%

Total amount (including tax): $54.0

Product name: Laptop

Quantity: 1

Tax included price per unit: $1500.0

Tax rate: 10.0%

Tax amount: $150.0

Original price (excluding tax): $1350.0