Creating a Java Product Class with Encapsulation and discount Method

Last update on May 16 2025 13:08:30 (UTC/GMT +8 hours)

Write a Java program to create a class called Product with private instance variables productName, productCode, and price. Provide public getter and setter methods to access and modify these variables. Add a method called applyDiscount() that takes a percentage and reduces the price by that percentage.

Sample Solution:

Java Code:

Product.java


// Define the Product class
public class Product {
    // Private instance variables
    private String productName;
    private String productCode;
    private double price;

    // Public getter for the productName variable
    public String getProductName() {
        return productName;
    }

    // Public setter for the productName variable
    public void setProductName(String productName) {
        this.productName = productName;
    }

    // Public getter for the productCode variable
    public String getProductCode() {
        return productCode;
    }

    // Public setter for the productCode variable
    public void setProductCode(String productCode) {
        this.productCode = productCode;
    }

    // Public getter for the price variable
    public double getPrice() {
        return price;
    }

    // Public setter for the price variable
    public void setPrice(double price) {
        this.price = price;
    }

    // Method to apply a discount percentage to the price
    public void applyDiscount(double percentage) {
        if (percentage > 0 && percentage <= 100) {
            this.price -= this.price * (percentage / 100);
        }
    } 
}

Main.java

public class Main {
      // Main method to test the Product class
    public static void main(String[] args) {
        // Create a new Product object
        Product product = new Product();

        // Set the product name, code, and initial price
        product.setProductName("Laptop");
        product.setProductCode("LT01233");
        product.setPrice(1100.00);

        // Apply a 8% discount to the product
        product.applyDiscount(8);

        // Print the details of the product
        System.out.println("Product Name: " + product.getProductName());
        System.out.println("Product Code: " + product.getProductCode());
        System.out.println("Price after discount: $" + product.getPrice());
    }
 }

Output:

Product Name: Laptop
Product Code: LT01233
Price after discount: $1012.0

Explanation:

Private Instance Variables: The productName, productCode, and price variables are declared as private to ensure encapsulation.
Public Getters and Setters: These methods provide controlled access to the private variables.

getProductName(): Returns the product name.
setProductName(String productName): Sets the product name.
getProductCode(): Returns the product code.
setProductCode(String productCode): Sets the product code.
getPrice(): Returns the price.
setPrice(double price): Sets the price.

applyDiscount Method: Takes a percentage and reduces the price by that percentage if the percentage is valid.
Main Method: Tests the functionality of the Product class by creating an instance, setting its properties, applying a discount, and printing the details.

Note on Encapsulation

Encapsulation works in the above exercise by:

Hiding Data: The private instance variables productName, productCode, and price are not accessible directly from outside the class.
Controlled Access: The public getter and setter methods provide controlled access to the private variables, allowing for validation and modification when necessary.
Data Integrity: Encapsulation helps maintain data integrity by ensuring that the internal state of the object can only be changed through well-defined methods.

For more Practice: Solve these Related Problems:

Write a Java program where the "Product" class prevents setting a negative price.
Write a Java program where the "Product" class applies bulk discounts dynamically.
Write a Java program where the "Product" class allows setting categories with predefined values.
Write a Java program where the "Product" class calculates the total sales revenue.

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