The open source GIS server project called GeoServer has chosen Apache Wicket for their web interface. I've been following their progress through the Nabble archives from a distance and saw them reach a formidable milestone today. David Winslow writes:

Hey all, I have reached my goal of >40% test coverage for all wicket modules (hooray!).

This is a great achievement and I hope for a bright future for the Wicket and GeoServer combination!