Wicket is a framework based on what made Java great i.e. Java itself. There is no xml based configuration or plugging things together. The presentation markup is in plain html. Errors are very clear and helpful.
I feel confident when refactoring with Wicket (since it is plain Java). Java tooling is excellent whereas xml, bytecode injection, dynamic proxy/introspection etc. tooling is not.
Unit testing in Wicket is very simple and easy to do.
Wicket provides a way of managing state which to me is quite intuitive and easy to use (and again no xml!). This makes work flows really easy.
Wicket does feel quite abstracted from the techie web side of things which is both good and bad. It is good in the fact that I focus on developing business logic. The bad is when I've got to do something that is out of the ordinary and not straight forward to do in Wicket.
On the whole I found it very productive in building web sites using a TDD approach.
this project does not have a short commit history. it switched repos (twice) and ohloh did not follow it correctly. wicket was started in april 2004. it is also NOT GPL and now contains no GPL code. there is certainly no conflict with ASL as it is now a top level apache project. the graph of code commits is also completely wrong as it lacks the history (all of my work, i might add and a very significant portion of even today's codebase)
Wicket is a component based web application framework which lets java developers think of web applications in terms of components which can designed upon object oriented principles.
A few points worth mentioning::
1.The html markup (& looks) remains intact in the html, without any scripting,special tags or code mix up & leaves room for ui designers to work independently.
2.Sessions are managed by the framework.
3.Above point does not make it session heavy as the concept of Models is simple and sound, letting them be detached from session & attached to session.
4.Ajax support with ajax components
5.Writing new components is a breeze.
6.Community & mailing lists are just great
"If you are a java developer, try to get the hang of wicket...And you might not want to return back to any other thing you were using for web front-end development.....theres a lot of hype on a lot of stuff out there for the job.Wicket experience is so solid that you will quit re-visiting it "