Last time I tried to write my Spring-MVC controllers in Groovy, I learned the hard way that they did not really play nice with each other, so I ended up moving as much as functionality possible to Groovy classes while using Java controllers proxying incoming requests. It seems things have changed since then now that I tried the same scenario with Groovy 2.1.3 & Spring-MVC 3.1.2, that's awesome!

So, here is an interesting use for Groovy Delegate transformation: adding request mappings from another class to your already existing controller.

You can just as well achieve the same result by extending the delegated class, but where is the fun in that :) ?