I'm pretty excited about this, personally. Our startup[1] is building mostly in Groovy and using Grails, and we've been very happy with the decision so far. To my mind, one of the biggest knocks on Groovy has been performance, so it's good to see them moving forward aggressively with taking advantage of invokedynamic and working to improve performance.

The JRuby guys got quite an improvement out of using invokedynamic, IIRC, so hopefully this bodes well for the future of Groovy. As others have said, Groovy is quite remarkable. To date, it remains my favorite JVM language (not to take anything away from Clojure, Scala, JRuby, Fantom, Nice, Beanshell, Jython, Kotlin, Fortress, Joy, Ceylon, etc).

[1]: Fogbeam Labs, the up-and-coming Open Source collaboration/knowledge-management company. http://www.fogbeam.com Go there now and sign up for our newsletter. It's not necessary for you to spend the rest of your day thinking about how cool Fogbeam Labs are, and how much you want to email all your friends and tell them about us too. But if you can remember a time when you were really excited about a company like Fogbeam Labs, then think back to those feelings and how that made you feel, and do the right thing.