Java "Not a Memory Hog" shock!

According to Xiaobin Lu on Java.net it is just the way the JRE maps the jar files in memory that makes Java look like it has a big footprint in (say) Task Manager. So they've rewritten the mapping in the latest build of Mustang. The really interesting thing is that the new mapping technique on Linux and Solaris works the way it always did on Windows and so saves 12-13% on real memory usage, as well as reducing the perceived usage. Java more efficient on Windows than on *nix - who'd have thunk it?