We tried out enunciate as well. It's good but didn't quite fit our needs...

You can run swagger with the built-in support via swagger-core/swagger-jaxrs. Play 1.4/2.0 support is there as well and a number of folks are creating support for other server frameworks. See the samples for integration:

https://github.com/wordnik/swagger-core/tree/master/samples

But to be honest, you can run the whole system with static files and zero server integration.

The downside of using javadocs is that you need to expose sourcecode/docs.