Java product
// Define the Product class class Product { private String name; private double price; private int quantity; private double taxRate; // Tax rate as a decimal (e.g., 0.08 for 8%) // Constructor to initialize the product public Product(String name, double price, int quantity, double taxRate) { this.name = name; this.price = price; this.quantity = quantity; this.taxRate = taxRate; } // Method to calculate the total cost including tax public double calculateTotalCost() { double subtotal = price * quantity; double taxAmount = subtotal * taxRate; double totalCost = subtotal + taxAmount; return totalCost; } // Getter...