Simple Java Program

Here is an example Java program. It is almost the smallest possible Java program. When it is run it writes Hello World! on the computer monitor. The details will be explained later.

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

This program can be created using a text editor such as the Notepad editor that comes with Windows. Details on how to do this will come later. The important thing for now is to understand that it is a text file saved on the hard disk. The file is named Hello.java.

A source program is a text file that contains a program (such as above) written in a programming language. Since the file contains characters (stored as bytes) it can not be directly executed (run) by the computer system. As a text file, you can print it, display it on the monitor, or alter it with a text editor.