LGTM I think this is in practice a safe compromise. If a file within a jar changes, then all things in the jar will appear to be updated, but I think this is reasonable.
Can refine in the future, to try to detect whether the date of an entry is 0 (or somehow invalid), and only revert to the jar file timestamp in that case. But I think it's worth going with this mod for now, since it should solve the issues at hand, and in practice, invalidating one jar is not as onerous as invalidating everything. http://gwt-code-reviews.appspot.com/1422802/ -- http://groups.google.com/group/Google-Web-Toolkit-Contributors
