This keyword usage in Java - Mini Project: Build & Apply

This keyword usage

📖 Scenario: Imagine you are creating a simple Java program to manage a book's details. You want to clearly understand how to use the this keyword to refer to the current object's properties.

🎯 Goal: You will build a Java class called Book with two properties: title and author. You will use the this keyword to set these properties inside the constructor and then print the book details.

📋 What You'll Learn

Create a class called Book with two String properties: title and author

Create a constructor for Book that takes two parameters named title and author

Use the this keyword inside the constructor to assign the parameters to the class properties

Create a method called printDetails that prints the book's title and author

Create a main method to create a Book object and call printDetails

💡 Why This Matters

🌍 Real World

Using <code>this</code> is common in Java when you want to clearly refer to the current object's properties, especially when parameter names match property names.

💼 Career

Understanding <code>this</code> is essential for writing clear and bug-free Java classes, which is a fundamental skill for Java developers.

1

Create the Book class with properties

Create a public class called Book with two String properties named title and author.

Java

public class Book {
    // Your code here
}

Need a hint?

Properties are variables inside the class but outside any method.

2

Add constructor using this keyword

Add a constructor to the Book class with parameters String title and String author. Use the this keyword to assign the parameters to the class properties title and author.

Java

public class Book {
    String title;
    String author;

    // Add constructor here
}

Need a hint?

The this keyword helps to distinguish between the class property and the constructor parameter with the same name.

3

Add method to print book details

Add a public method called printDetails inside the Book class that prints the book's title and author using System.out.println. Use this.title and this.author to access the properties.

Java

public class Book {
    String title;
    String author;

    public Book(String title, String author) {
        this.title = title;
        this.author = author;
    }

    // Add printDetails method here
}

Need a hint?

Use this to refer to the current object's properties inside methods.

4

Create main method and display book details

Add a main method inside the Book class. Inside main, create a Book object with title "Java Basics" and author "Alice". Then call the printDetails method on this object to display the book details.

Java

public class Book {
    String title;
    String author;

    public Book(String title, String author) {
        this.title = title;
        this.author = author;
    }

    public void printDetails() {
        System.out.println("Title: " + this.title);
        System.out.println("Author: " + this.author);
    }

    // Add main method here
}

Need a hint?

The main method is the program's starting point. Create the object and call the method to see the output.