How do I get a Java program I installed running?
<p>I downloaded a program implemented in Java (in this case, <a href="http://julian.togelius.com/mariocompetition2009/index.php" rel="nofollow">http://julian.togelius.com/mariocompetition2009/index.php</a>). I first tried opening the Play.class file with Java, but it spit out an error i couldn't see because the console window disappeared so fast. I replicated this on the command line, and got the following error:</p>

<pre><code>Exception in thread "main" java.lang.NoClassDefFoundError: Play/class
Caused by: java.lang.ClassNotFoundException: Play.class
        at java.net.URLClassLoader$1.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.net.URLClassLoader.findClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClass(Unknown Source)
        at java.lang.ClassLoader.loadClassInternal(Unknown Source)
Could not find the main class: Play.class.  Program will exit.
</code></pre>

<p>What do i have to do to get this to run properly? (If this belongs on Superuser then that's fine.)</p>
