Introduction to Programming in Java

This page extends on the previous resource to delve deeper into Java itself, relating its use to its history.

5. "Hello World"

Anytime you learn a computer programming language, it is tradition that the first program you write should be to make your computer say, "Hello World". This is a small feat, but is a good opportunity to make sure that you installed the JDK properly.

The Java compiler reads basic text files. Open up a text editor like Notepad (Don't use a complex program like Word for this). Type this code, remembering that Java is case-sensitive:

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

Save this file as Start your system's command line and navigate to the folder that you saved to. Type javac This runs the java compiler, javac, and creates a class file, which contains the bytecode for the application. Next type java -cp . HelloWorld. This runs the class file that was just created by the compiler. Your console should print:

Hello World!