Real-world modeling in Java - Mini Project: Build & Apply

Modeling a Library System in Java

📖 Scenario: You are helping to build a simple library system. The library keeps track of books and their availability. You will create a basic model using Java classes and variables to represent books and their status.

🎯 Goal: Build a Java program that models books in a library with their titles and availability status. You will create a class, add variables, and print the book details.

📋 What You'll Learn

Create a Book class with two variables: title (String) and isAvailable (boolean).

Create an instance of Book with the title "Java Basics" and availability true.

Add a method to display the book's title and availability status.

Print the details of the created book.

💡 Why This Matters

🌍 Real World

Modeling objects like books helps build software for libraries, bookstores, or inventory systems.

💼 Career

Understanding how to create classes and objects is fundamental for software development jobs involving real-world data.

1

Create the Book class with variables

Create a public class called Book with two variables: a String called title and a boolean called isAvailable.

Java

public class Book {
    // Your code here
}

Need a hint?

Think of a book as having a name and a yes/no status for availability.

2

Create a Book object with title and availability

Inside a public static void main(String[] args) method in a class called Library, create a Book object named book1. Set its title to "Java Basics" and isAvailable to true.

Java

public class Book {
    String title;
    boolean isAvailable;
}

public class Library {
    public static void main(String[] args) {
        // Create book1 and set title and availability
        // Your code here
    }
}

Need a hint?

Create the object with new Book() and assign values to its variables.

3

Add a method to display book details

Add a public method called displayInfo inside the Book class. It should print the book's title and availability in the format: Title: Java Basics, Available: true.

Java

public class Book {
    String title;
    boolean isAvailable;
    
    // Add displayInfo method here
    // Your code here
}

public class Library {
    public static void main(String[] args) {
        Book book1 = new Book();
        book1.title = "Java Basics";
        book1.isAvailable = true;
    }
}

Need a hint?

Use System.out.println to print the combined string with variables.

4

Print the book details

In the main method of Library, call the displayInfo method on book1 to print its details.

Java

public class Book {
    String title;
    boolean isAvailable;
    
    public void displayInfo() {
        System.out.println("Title: " + title + ", Available: " + isAvailable);
    }
}

public class Library {
    public static void main(String[] args) {
        Book book1 = new Book();
        book1.title = "Java Basics";
        book1.isAvailable = true;
        // Call displayInfo on book1
        // Your code here
    }
}

Need a hint?

Use book1.displayInfo(); to show the book details.