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The Hello World Program with Detailed Explanation of Java Program

The "Hello World" program is a simple program that prints the message "Hello, World!" to the console. Let's go through the program and explain each keyword in detail:

public class HelloWorld {

    // 'public' is an access modifier. It indicates that the class is accessible from anywhere.

 

    public static void main(String[] args) {

        // 'public', 'static', and 'void' are modifiers for the main method.

        // 'public' makes the method accessible from anywhere.

        // 'static' indicates that the method belongs to the class and not to an instance of the class.

        // 'void' means that the method does not return any value.


        System.out.println("Hello, World!");

        // 'System' is a class in the java.lang package.

        // 'out' is a static member of the System class, representing the standard output stream.

        // 'println' is a method of the PrintStream class (type of 'out') used to print a line of text.

                // ';' is a statement terminator, marking the end of the statement.

    }

}


Explanation of each keyword:

1. public` (Access Modifier):

   - The `public` keyword is an access modifier. It makes the class or method accessible from anywhere. In this case, the class `HelloWorld` and the `main` method are marked as public.

2. class (Class Declaration):

   - The `class` keyword is used to declare a class. In this program, the class is named `HelloWorld`.

3. static (Static Keyword):

   - The `static` keyword is used to declare a method or variable that belongs to the class rather than an instance of the class. In the `main` method, it allows the method to be called without creating an instance of the class.

4. void (Return Type):

   - The `void` keyword is used as the return type of a method to indicate that the method does not return any value.

5. main` (Main Method):**

   - `main` is the name of the method. It is the entry point of a Java program. When the Java program is executed, it starts by calling the `main` method.

6. String[] args (Command-Line Arguments):

   - `String[] args` declares a parameter named `args` of type array of strings. It allows the program to accept command-line arguments when it is executed.

7. System.out.println` (Print Statement):

   - `System.out.println` is a method that prints the given message to the standard output (console). In this case, it prints "Hello, World!".

8. `;` (Statement Terminator):

   - The semicolon `;` is used as a statement terminator in Java, marking the end of a statement.


Now, let's see an example of executing the program and understanding the output:

public class HelloWorld {

    public static void main(String[] args) {

        System.out.println("Hello, World!");

    }

}


When this program is executed, it will output:


Hello, World!


This simple program serves as an introduction to the basic structure of a Java program and the usage of keywords.

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