GWT activities and places do not work with gwt code splitting facility. Recently i have changed GWT activities and places sample so that it works with GWT code splitting feature and push the new sample into github.
In this sample, split points occur on getting activity by ActivityMapper, i write a new kind of ActivityMapper called AsyncActivityMapper which can get activities asynchronous, and also i write a new kind of ActivityManager called AsyncActivityManager (copy and paste gwt ActivityManager class with minor changes) that work with AsyncActivityMapper.

Have a nice time.