Tried running one of my other favorite Java programs
Retriever using Java Portable Launcher similar to the successful
muCommander test.
It doesn't compare in terms of features to Free Download Manager (
http://www.portablefreeware.com/index.php?id=1364), but it was another test for the JAR launcher and its cross-platform.
The program has an installation system (even the JAR file is labeled "inst") that goes outside of the JAR Launcher. Even unchecking all available options and assocations, it still creates quite a few registry entries:
HKCU\Software\JavaSoft\Prefs\/Halogen/Ware
HKCU\Software\Classes\Retriever.Retriever.jar.HalogenWare
The program does appear to function, so users who don't care so much about the registry issues can still run Retriever in Windows and potentially off a USB drive. It also may be a workaround for users who dont' want to install Java or don't have admin rights.