I recently discovered jvisualvm and have been using it to profile mkgmap. One thing I haven't discovered yet is how to profile an application from the start - its trivial to attach to an already running java app using the gui but if it's already running, you could miss some useful info. So, the attached patch is a little kludge that lets you start mkgmap but then it immediately pauses for a little while (long enough to attach jvisualvm to it and turn on the profiling, etc.) before it gets down to work. To use this, just add -Dsleep-on-startup=30 or similar to your Java args. Can anyone think of a better way of achieving the same goal? Mark