when starting the wicket-examples (or when executing 'mvn install' on the wicket source dir) java will launch an application window on the desktop (at least on os x it does). this is happening when using awt-classes. java will allocate a desktop window unless you tell it to run in headless mode.
for a non-desktop-bound server application this makes sense.
headless mode is enabled by setting system property 'java.awt.headless' to 'true'.
I attached a patch...