Why object-oriented programming is used in Java - See It in Action

Why Object-Oriented Programming is Used

📖 Scenario: Imagine you are building a simple program to manage a library. You want to keep track of books and their details like title, author, and number of pages.

🎯 Goal: You will create a basic Java program that shows why object-oriented programming (OOP) is useful by organizing book information into objects.

📋 What You'll Learn

Create a class called Book with three fields: title, author, and pages

Create an object of Book with specific values

Add a method to display the book details

Print the book details using the method

💡 Why This Matters

🌍 Real World

OOP is used to model real-world things like books, cars, or people as objects in programs. This makes programs easier to understand and maintain.

💼 Career

Many software jobs require understanding OOP concepts to build scalable and organized applications.

1

Create the Book class with fields

Create a class called Book with three fields: String title, String author, and int pages.

Java

// Your code here

Need a hint?

Think of a class as a blueprint for creating book objects.

2

Create a Book object with values

Inside a Main class with a main method, create a Book object called myBook. Set title to "Java Basics", author to "Alice", and pages to 250.

Java

class Book {
    String title;
    String author;
    int pages;
}

public class Main {
    public static void main(String[] args) {
        // Create a Book object called myBook and set its fields
        
    }
}

Need a hint?

Use new Book() to create the object and dot notation to set fields.

3

Add a method to display book details

Add a method called displayInfo inside the Book class that prints the book's title, author, and pages in one line.

Java

class Book {
    String title;
    String author;
    int pages;
    // Add displayInfo method here
}

public class Main {
    public static void main(String[] args) {
        Book myBook = new Book();
        myBook.title = "Java Basics";
        myBook.author = "Alice";
        myBook.pages = 250;
    }
}

Need a hint?

The method should print all fields in one line separated by commas.

4

Print the book details using the method

In the main method, call myBook.displayInfo() to print the book details.

Java

class Book {
    String title;
    String author;
    int pages;
    
    void displayInfo() {
        System.out.println(title + ", " + author + ", " + pages + " pages");
    }
}

public class Main {
    public static void main(String[] args) {
        Book myBook = new Book();
        myBook.title = "Java Basics";
        myBook.author = "Alice";
        myBook.pages = 250;
        // Call displayInfo method here
    }
}

Need a hint?

Use the object name myBook followed by dot and method name displayInfo().