Primitive vs reference storage in Java - Hands-On Comparison

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Primitive vs Reference Storage in Java

📖 Scenario: Imagine you are organizing a small library. You want to keep track of the number of books and the details of each book separately.

🎯 Goal: You will create variables to store the number of books (a simple number) and the details of each book (like title and author) using objects. This will help you understand how Java stores simple values and objects differently.

📋 What You'll Learn

Create a primitive variable to store the number of books

Create a class called Book with two fields: title and author

Create an object of Book with specific values

Print the number of books and the book details

💡 Why This Matters

🌍 Real World

Understanding how Java stores simple data and objects helps when managing data in apps, games, or websites.

💼 Career

Knowing primitive vs reference storage is essential for Java developers to write efficient and bug-free code.

1

Create a primitive variable for the number of books

Create an int variable called numberOfBooks and set it to 3.

Java

# Your code here

💡 Need a hint?

Use int to store whole numbers like the count of books.

2

Create a Book class with title and author fields

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

Java

public class Library {
    public static void main(String[] args) {
        int numberOfBooks = 3;
    }
}

// Your code here

💡 Need a hint?

Define a class outside Library with two String fields.

3

Create a Book object with specific title and author

Inside the main method, create a Book object called myBook. Set its title to "Java Basics" and author to "Alice".

Java

public class Library {
    public static void main(String[] args) {
        int numberOfBooks = 3;
        // Your code here
    }
}

class Book {
    String title;
    String author;
}

💡 Need a hint?

Create the object with new Book() and assign values to fields using dot notation.

4

Print the number of books and book details

Use System.out.println to print the numberOfBooks, then print the title and author of myBook each on a new line.

Java

public class Library {
    public static void main(String[] args) {
        int numberOfBooks = 3;
        Book myBook = new Book();
        myBook.title = "Java Basics";
        myBook.author = "Alice";
        // Your code here
    }
}

class Book {
    String title;
    String author;
}

💡 Need a hint?

Print the primitive variable and then the object's fields using System.out.println.