I just read the blog post about debugging without symbols. If this really works, it probably is the coolest thing ever. I have been seriously annoyed about not having debug symbols in the JDK for a long time now.
Do I need to turn anything special on for this to work? I'm using IU-132.637 on OS X and it only shows "Local variables debug info not available" in the debugger. That's the same for my own classes if I turn off debugging symbols (like in the blog post) and for JDK classes.