...and the GWTShell executes your *Java* code, so the regexps have to
be Java-regexp-compatible for your app to work in Hosted Mode.
In a few words:
Hosted Mode, so developping and debugging will become a pain
- if you use Java-only regexp constructs, your app will run in Hosted
Mode but will fail in "web mode"
and if it fails in Hosted Mode, then find an alternate that's still
base your devs on the Java regexp syntax, you'll only notice the
incompatibilities when testing in web mode, which generally happen
late in the development process...