we're using the latest GWT version in master UI now .
We can start using Java 8 syntax in our frontend code. GWT 2.8 also brings
partial support for Java 8 standard library APIs, see "JDK emulation" at
 for details.
Effectively, all Engine (Java Maven) modules  are now Java 8 source &
 except backend/manager/modules/extensions-api-root
should take advantage of new web APIs (e.g. using ES6 Maps to implement
Java HashMap) as well as general performance improvements (e.g. using a
faster "long" emulation).
GWT 2.8 removes deRPC (direct-eval RPC) mechanism but that's OK because
we're already using the standard GWT RPC .
There are no changes to existing build & development process:
- debugging via Java IDE (aka Classic Dev Mode) remains the default debug
- debugging via browser (aka Super Dev Mode) can be enabled via
DEV_BUILD_GWT_SUPER_DEV_MODE flag 
 example: $ make gwt-debug DEBUG_MODULE=webadmin
Note that in GWT 2.8 the Super Dev Mode is the new default debug method
(with Classic Dev Mode being deprecated).
There are still some post-upgrade tasks to do, we're tracking them on
If you encounter any issues related to GWT compilation or debugging, let me