At my current assignment, I needed to get my fellow developers up to speed with Wicket. So I put together a one day course that taught them enough to join in on the work of a current application. Everything is publicly available on GitHub here: https://github.com/perty/wicket-kurs.
You get a starting plate for a complete web application with database backend accessed through Spring Data JPA. Also, there is a Power Point presentation that guides you through the exercises. Very little is spent on Wicket philosophy and concepts to the benefit of hands on coding.