Static vs non-static behavior in Java - Hands-On Comparison

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Static vs Non-Static Behavior in Java

📖 Scenario: Imagine you are creating a simple program to track the number of books created in a library system. Each book has its own title, but the total number of books is shared across all books.

🎯 Goal: You will build a Java program that shows the difference between static and non-static behavior by counting how many book objects are created and displaying each book's title.

📋 What You'll Learn

Create a Book class with a non-static title variable

Add a static variable bookCount to count all books created

Create a constructor that sets the title and increments bookCount

Write code to create multiple Book objects

Print each book's title and the total number of books using static and non-static variables

💡 Why This Matters

🌍 Real World

Tracking shared data like total users, total sales, or total items created is common in many software systems.

💼 Career

Understanding static vs non-static behavior is essential for writing efficient and correct Java programs in professional development.

1

Create the Book class with a non-static title

Create a class called Book with a non-static String variable called title. Add a constructor that takes a String parameter called title and sets the class variable this.title to it.

Java

public class Book {
    // Your code here
}

💡 Need a hint?

Remember, non-static variables belong to each object. Use this.title to set the instance variable.

2

Add a static variable to count books

Inside the Book class, add a static integer variable called bookCount and initialize it to 0. Then, inside the constructor, add code to increase bookCount by 1 each time a new Book object is created.

Java

public class Book {
    String title;
    // Your code here

    public Book(String title) {
        this.title = title;
        // Your code here
    }
}

💡 Need a hint?

Static variables belong to the class, not to individual objects. Increment bookCount inside the constructor.

3

Create multiple Book objects in main method

Create a public static void main(String[] args) method inside a class called Library. Inside main, create three Book objects with titles "Java Basics", "Python Guide", and "Web Development".

Java

public class Book {
    String title;
    static int bookCount = 0;

    public Book(String title) {
        this.title = title;
        bookCount++;
    }
}

public class Library {
    public static void main(String[] args) {
        // Your code here
    }
}

💡 Need a hint?

Remember to create the Library class and write the main method inside it. Use the new keyword to create objects.

4

Print each book's title and total book count

Inside the main method, add code to print each book's title using System.out.println and the non-static title variable. Then print the total number of books created using the static variable Book.bookCount.

Java

public class Book {
    String title;
    static int bookCount = 0;

    public Book(String title) {
        this.title = title;
        bookCount++;
    }
}

public class Library {
    public static void main(String[] args) {
        Book book1 = new Book("Java Basics");
        Book book2 = new Book("Python Guide");
        Book book3 = new Book("Web Development");

        // Your code here
    }
}

💡 Need a hint?

Use System.out.println to print each book's title and the static bookCount with the class name Book.bookCount.