You are allowed to do so (to redistribute the JRE) but it won't be simple, and might need to unpack the JRE somewhere. Somehow, it is simpler to tell your friend to install Java and be done for it, he will have it available for further demos or applets and so on.

Oh, ok. I thought it would be simpler to integrate JRE. Not everybody likes to install stuff they won't normally need on their pc. But this is another discussion ;) I'll have to look further to find more information. Thank you anyhow.

You can take the JRE folder from your PC and just copy it to your friend's PC (no registry change if you are on Windows, etc. Delete folder and it is no longer there). But then you have to run the jar using command line with proper incantations (full paths to java exe, correct classpath, etc.).

Now, there are some packagers for Java applications that might do the magic, but I don't know if they can pack the JRE as well.

I found JSmooth first, but this hasn't been updated since 2007 and didn't embed jre. Now I found a very nice looking Java-Tool called Launch4J. Very up to date and looks very promising and is open source too. Should do all I want and much more. I'll struggle a bit with it and report how it went.

For the record, Launch4j is used by Processing itself, to run the PDE... Sometime, on my old computer, I got a Launch4j error because the CPU was overloaded...

Just found an article on the topic: Convert Java to EXE - Why, When, When Not and How

Yes, I've found this too. A good tutorial on making Java programs portable with Launch4J can be found on the Informit-Site. Helas, it didn't help me on making it work ;) I can't make it find the main class. With JSmooth at least this worked ^^ Any ideas?

Edit: Oh this was so easy....

This is the xml if anyone cares to examine, nothing fancy. The important thing was to add both jars, core.jar and my .jar and provide the class name wich is simply the name of the sketchbook-file. I simply copied the processing java directory into mine and that's all there is to it. The jdkonly pref was only for testing purposes. Normally I wouldn't do this, but allow to use the installed version if found.

1. - <launch4jConfig>
     <dontWrapJar>false</dontWrapJar>
     <headerType>gui</headerType>
     <jar>C:\!portable\visnov_002\lib\visnov_002.jar</jar>
     <outfile>C:\!portable\visnov_002\visnov.exe</outfile>
     <errTitle />
     <cmdLine />
     <chdir>.</chdir>
     <priority>normal</priority>
     <downloadUrl>http://java.com/download</downloadUrl>
     <supportUrl />
     <customProcName>false</customProcName>
     <stayAlive>false</stayAlive>
     <manifest />
     <icon />
   - <classPath>
     <mainClass>visnov_002</mainClass>
     <cp>lib\visnov_002.jar</cp>
     <cp>lib\core.jar</cp>
     </classPath>
   - <jre>
     <path>java</path>
     <minVersion>1.5.0</minVersion>
     <maxVersion />
     <jdkPreference>jdkOnly</jdkPreference>
     </jre>
     </launch4jConfig>

Of course now my pal asked me to have a ONE FILE ONLY solution. Unfortunately I had to send him to hell ;)