External links take you outside the scope of Wicket. They can come in handy when you keep your links e.g. in a database.
To JavaLobby
To The Server Side
<a href="#" target="_new" wicket:id="externalLink1">this body will be replaced</a>
add(new ExternalLink("externalLink1", "http://www.javalobby.org", "To JavaLobby"));