Yeah, the adoption is pretty good, definitely compared to Jython / JRuby. Multiple conferences dedicated primarily to groovy / grails (gr8conf US coming up on Minneapolis on 30-31).
I think Grails is driving a lot of adoption, but I also see it popping up in vendor products that need a scripting language or DSL that integrates with Java easily. Neo4J and Cloudify (Gigaspaces product) come to mind as recent examples.
Yep. A lot of groovy adoption is "under the radar" precisely because it blends so seamlessly with Java. It may just be a build script or used in unit tests, but it is popping up all over the place.
Also under the radar because such companies using Groovy sometimes ask us to not speak publicly about the fact they're using Groovy... to my great disappointment!
I think Grails is driving a lot of adoption, but I also see it popping up in vendor products that need a scripting language or DSL that integrates with Java easily. Neo4J and Cloudify (Gigaspaces product) come to mind as recent examples.