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(d) Creating multi-clases with main()
In Java, you can create an object of a class and utilise it in another class. In Java
this is commonly employed for improved class organisation, where one class
encompasses all attributes and methods, while another class contains the main() Chapter Five: Object oriented programming with Java
method that carries the code to be executed. Note that, in the real world, when you
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develop applications, small applications can be accommodated by a single class, but
larger applications often require multiple classes. Very important to note is that the
name of the Java file must corresponds to the class name. In Program Example 5.17,
learn by establishing two classes: Book.java and Application1.java with the main
method. These should be contained within the same directory.

Program Example 5.17:

Java program to demonstrate multiple class Book.java and Application1.java

public class Book {
int x = 117;
}
class Application1 {
public static void main(String[] args) {
Book myApp = new Book();
System.out.println(myApp.x);
}
}

Output:

When two class files compiled, it will give you the output:

Figure 5.18: Demonstrating multiple class

When you run the file that contain the main method, for this case, Application1.
java you will get the output which is the object created from the main class Book.
java:

Figure 5.19: Demonstrating multiple class

347
Student’s Book Form Five

Computer Science Form 5.indd 347 23/07/2024 12:34