About a month ago I did a prototype on my laptop of changing VirtualFile.toURL() to return a VFS based URL. I got it up in working, but ran into a lot of problems when using VFS based URLs with a URLClassLoader. The way I had it working was that a URL Handler returned a VirtualFileURLConnection object. This class delegated to a VirtualFile to openStreams and such. VirtualFile.toURL() would return a "vfs" base URL. While VirtualFileHandlers remained untouched and returned their real underlying URL. For Jars I ran into a lot of Streaming problems where there would be pre-mature end-of-file errors when loading classes. This was solved by creating ByteArrayInputStreams around any loading of jar entries. I also found that the URL Classloader implementation worked differently depending on whether the URL ended in "/" or not. What scared me the most about this process was that I had to hack Sun specific by decompiling it to understand what the problems were as most of the behaviors I had to debug were not documented. I'm doing a second iteration of this code right now. One thing I'm going to try to do is to not return a VirtualFileURLConnection from the VFS protocol Handler, but instead return VirtualFileHandler.toURL().openConnection(). I think this may solve a lot of the problems that were encountered initially. View the original post : http://www.jboss.com/index.html?module=bb&op=viewtopic&p=3990063#... Reply to the post : http://www.jboss.com/index.html?module=bb&op=posting&mode=reply&a...