Recently Apple released Safari 5, which included a bug where non-integral right-shifts were not being evaluated properly. There were several reports, both internally and externally, of GWT-based applications unexpectedly crashing when running in Safari 5 (including Google Wave). Upon further inspection of the crash, we determined that the bug is triggered when calling several of GWT's array sorting methods, which in turn perform non-integral right-shifts as part of the compiled code.
That's the bad news. The good news is that we have a fix for this issue, plus several other house keeping items that we've rolled into a 2.0.4 release, which can be downloaded from GWT’s main download site.
If you’re experiencing the Safari crash, you’ll need to recompile and deploy your GWT app. The changes in 2.0.4 are completely compatible with your existing 2.0 app, and should have no negative impact. To that extent we’ve already dogfooded 2.0.4, verifying that it fixes the Wave crash that was originally reported.