You assign the lazy jars to groups (can't remember the technical name off top of head - "parts" ?), so that JWS knows "part A is linked to parts B and C", for instance.
Not very helpful, I'm afraid, but don't have all my downloaded JWS refs here at work
. If you grab the big PDF functional specification for webstart, you'll find it's not so much a spec as a manual
. So, go to the java site, find JWS, and get that "spec" (manual) - it's great, very readable (pity it's PDF only, instead of something intelligent like HTML).