In the preceding section, we generated a Java file named Main.java, employing the subsequent code to display “Hello World” on the screen:

Main.java:

public class Main {
  public static void main(String[] args) {
    System.out.println("Hello World");
  }
}

Example explained

In Java, every line of executable code must reside within a class. In our illustration, we designated the class as Main. It’s conventionally recommended that class names begin with an uppercase letter.

Please note that Java is case-sensitive, meaning “MyClass” and “myclass” are distinct.

Furthermore, the Java file’s name should correspond to the class name. When saving the file, use the class name followed by “.java”. To execute the example provided on your machine, ensure that Java is correctly installed. Refer to the “Get Started” chapter for Java installation instructions. The expected output is:

The main Method

The presence of the main() method is mandatory and it is a staple in every Java program.

public static void main(String[] args)

Any code inside the main() method will be executed.
Don't worry about the keywords before and after main; 
you'll learn about them gradually as you progress through this tutorial.

public static void main(String[] args) {
  System.out.println("Hello World");
}