Adjusting to life in GWT-land
First use the gwt-mpv framework (http://www.gwtmpv.org/) - it will save your sanity and quite possibly your soul. One of our awesome developers, Stephen has created a very nice model, view, presenter framework on top of GWT that removes a huge amount of boilerplate. It has some really nice stuff like validation, two way data binding, code generation for tedious boilerplate and more. Your fingers and brain will thank you for saving them from the verbosity of vanilla GWT, trust me...I’m an engineer.
Even though you’re writing in Java - you’re still working on the client side. Custom events are great for decoupling and facilitating easy testing of your objects as you only have to talk to a single event handler instead of multiple objects. Don’t go overboard though, you still want to avoid having events that call events that call events etc. as you’ll end up jumping all over the place trying to find out what really was supposed to happen when the original event fired.