Example 2 for Default Constructor

Book.java

class Book {
    String title;

    // A no-argument constructor
    Book() {
        title = "Unknown";
    }
}

public class Main {
    public static void main(String[] args) {
        Book mysteryBook = new Book();
        System.out.println("Book title: " + mysteryBook.title); // Outputs: Book title: Unknown
    }
}