Basically, for testing purposes, I've got a JavaFX applet that shows text entry fields - basically a simple format where you see

_______________________________________
|                ___________________   |
|  Your name     |__________________|o |
|                                      |
|                ___________________   |
|  Something     |__________________|o |
|                                      |
|                                      |
|                ______  ______        |
|                |Prev | | Next|       |
|                |_____| |_____|       |
|______________________________________|

Neater still, it has a provision for server-side validation of the components. This took a little doing (some Java code that starts a background thread, and a Java interface for running it and performing callbacks which is implemented over a JavaFX class) - so when the user stops typing into a field for a few seconds, the applet can communicate with the server (presumably using the same mechanisms as Wicket's built-in AJAX support); the little "o" you see beside each text field shows whether the data is good or not, and while the background part is running (currently just a Thread.sleep() - I wanted to see if I could get this working at all).

But while what I've got is a really rough prototype, it proves you can do it (yes, you can do similar things with AJAX, but well, it's AJAX :-)).

Now, whether the world has any use for this is another question - but it could be interesting to make generic data entry applets with lovely UIs, which could simply be embedded in a Wicket component (and skinned with your site's own CSS - though this actually seems to be a little broken in JavaFX at the moment). Drop the component on your page, and, voila.

Now, of course, the hard side is the server<->client communication - that's next. Or maybe I'll take the weekend off...that would be unusual :-)