Dev mode doesn't work

[solomatov]

When I change a file, nothing gets recompiled. It seems that you use built jars which never change.

[ekuefler]

See the description of the java_roots flag at https://github.com/bazelbuild/rules_gwt#gwt_application. In particular, if your java package hierarchy isn't rooted at java or src/main/java relative to your WORKSPACE file, you probably need to set this flag for Bazel to be able to see your source files.