//*******************************************************************
// Dear CompileJava users,
//
// CompileJava has been operating since 2013 completely free. If you
// find this site useful, or would otherwise like to contribute, then
// please consider a donation (link in 'More Info' tab) to support
// development of the new CompileJava website (stay tuned!).
//
// Most sincerely, Z.
//*******************************************************************

import java.lang.Math; // headers MUST be above the first class

// one class needs to have a main() method
public class HelloWorld
{
  // arguments are passed using the text field below this editor
  public static void main(String[] args)
  {
    OtherClass myObject = new OtherClass("Hello World!");
    System.out.print(myObject);
  }
}

// you can add other public classes to this editor in any order
public class OtherClass
{
  private String message;
  private boolean answer = false;
  public OtherClass(String input)
  {
    message = "Why, " + input + " Isn't this something?";
  }
  public String toString()
  {
    return message;
  }
}

More Info

Online Java IDE

What is this?

Fast and functional online Java compiler
Always runs the latest version of Java

Functions:

Paste source to GitHub and share with others
Download compiled source files (.java, .class, .jar)
*NEW! Import a Gist (press F3)*

Features:

Many themes included for ease of coding
Optional command-line arguments
Auto-splits multiple public classes to files
Applet support, including JPanel *READ THIS!*

Other Notes:

Programs have a 5-second time limit
Send bug reports/feature requests here please

Shortcuts:

F11 : standard browser full-screen mode
F12 : Zen Mode (distraction-free coding)
F2 : shortcut to compile code (useful in Zen Mode)
F3 : import a Gist (universal support coming)
F4 : runs Applet (after compilation) in window

*shortcuts only work if 'focused' on code box