[mkgmap-dev] splitter and java 1.5?

I tried to run the splitter on massachusetts.osm (from cloudmade) because my mac with a paltry 2G of ram couldn't cope in one piece. I got an exception about bad versoin number in class file, and I wonder if the splitter requires java 1.6? It would be nice if all the osm java code worked with 1.5, which is still current with even OS X 10.5.x, or at least if the splitter page at http://www.mkgmap.org.uk/page/tile-splitter explained the prereqs.