Java Hello world application

If you're just getting started with Java it may help to have a simple first class to look at. In the code below I'm showing a sample Java class named HelloWorld.

public class HelloWorld

  public static void main(String[] args)
    System.out.println("Hello, world");


To use this class, save it to your system in a file named Then, compile it to Java bytecode with this command:


This javac command creates a new file named HelloWorld.class which contains the bytecode for this class. (It's a binary file you can't really look at with an editor.) You can think of the javac command as meaning "java-compile" if that helps.

To run your new program just type this command:

java HelloWorld

This java command starts up your JVM, loads your class file (HelloWorld.class), and then runs the program. The result is that it should print the following output:

Hello, world