How to use groovy as scripting language.

I read something about the possibility to use groovy as main development language in Vaadin.
In my environment, however, I need to use groovy as scripting language in order to modify, on the fly, with some external script, layout and behaviour of some vaadin applications.
Is it possible ?
How ?
I’m not in love with groovy and then other, different, ideas and languages fitting my requiremente could be well accepted.

Probably this addon will help you:

I already saw it but I didn’t unerstand how to use in my situation.
In the example the whole UI is done with groovy, I need to modify an existing UI and its behaviour with groovy (or other language).
Could You suggest how?

Try to just replace your normal vaadin servlet with groovy servlet (from addon) in web.xml.
Try to launch application - everything shold work as before.
Then try to change one controller into groovy and try to run application.
If everything is ok, try to modify controller and check re-compilation on the fly.

Can’t guarantee that this will work, but it should - at least worth a try.

If you need groovy only for hot redeploy, consider using vaadin team approach - use jetty, which support automatic code reload (try to search this forum, this approach is described somewere)

However I don’t need it to hot redeploy but in order to make my application customizable in some way from users without change in my base code.
Could You suggest the way ?
I can also use JQuery or every library usefull in order to reach my goal.