Hello, World! Program in Java

Hello, World Program in Notepad:

Open Notepad and type the following code:

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

Save the file as Hello.java. You can do this by clicking on File > Save As and then selecting the directory where you want to save the file. Make sure to type the filename as Hello.java and select All Files in the Save as type dropdown menu.

Open the command prompt and navigate to the directory where you saved the Hello.java file.

Compile the program by typing javac Hello.java and pressing Enter.

If there are no errors, run the program by typing java Hello and pressing Enter. The program will output “Hello, world!” in the console. To keep your console clean, you can clear the java console before running the next command.

java -cp /tmp/jLRff3bu2p HelloWorld
Hello World

Output
Hello World

Java Hello World Program Explanation

• class: The class keyword is used to declare a class in Java.
• public: The public access modifier makes the class visible to all.
• static: The static keyword means that the method can be called without creating an object of the class.
• void: The void return type means that the method does not return any value.
• main: The main method is the entry point of the program.
• String[] args: The System.out.println() method is used to print a string to the console.
• System.out.println(): The System.out.println() method is used to print a string to the console.

Java Comments

It is useful to place a comment in place to indicate what you are doing. It is added into the program for making the program easier to understand and these are not compiled by the compiler or interpreter. It is useful if you want someone else to be able to ever read your code.

There are two ways to declare comment in java which are as follows:

• Single Line comment
• Multi-Line comment

Single Line comment in Java:

It is used to apply the comment on a single line. To apply single line comment // is used.

Example:

System.out.println("Hello World");  // It will print Hello World

Multi-Line comment in Java:

It is used to apply the comment on multiple lines.

Example:

System.out.println("Hello World");  /*  It will print
Hello World */

Keywords in Java Programming

Keywords are also known as reserved words which express a special meaning to the compiler and interpreter. Keywords in Java are –