First Java program to print "Hello World"

First Java program

This is our first program in Java. In this program, we will print “hello world” message on the screen and see how the basic Java program is compiled and executed by Java. This has been a tradition to create the first program in any programming language which prints hello world on the screen so we will do the same and make the same program. Java is an object-oriented programming language, which is widely used all over the world by the majority of developers to develop large web and desktop applications. Java is also a pioneering technology in the industry that is used for mobile(Android) app development.

The "Hello World" program

Write the following code in your favorite editor and compile it.

Compile the program using the following command
javac HelloWorld.Java

And execute your program using the command

java HelloWorld

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

Structure of "Hello World" Program

"Hello World" program in Java

Java Keywords

A keyword is a reserved word or literal having some special meaning to perform or represent something in a programming language. The keywords can't be used as identifiers or variable names in a Java Program.

Following is the list of the Java keywords.

Java Keywords

abstract	continue	for	new	switch
assert***	default	goto*	package	synchronized
boolean	do	if	private	this
break	double	implements	protected	throw
byte	else	import	public	throws
case	enum****	instanceof	return	transient
catch	extends	int	short	try
char	final	interface	static	void
class	finally	long	strictfp**	volatile
const*	float	native	super	while

*	not used
**	added in 1.2
***	added in 1.4
****	added in 5.0

Running a Java Program with command-line arguments

1. write a program and compile with the command
javac HelloWorld.Java


2. Execute your program using the command
java HelloWorld Java Python

/****Running with command-line arguments**********/
public class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello "+args[0]);
        System.out.println("Hello "+args[1]);
    }
}

Output:

Hello Java
Hello Python

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