I had the great privilege earlier this week to meet with some household names in the Java, Python, Jython, Perl, Groovy and XML worlds.
The meeting was instantiated by Tim Bray to talk about dynamic languages on the JVM.
I met Samuele Pedroni for the first time and had the pleasure of watching him step through some of the details of Jython's implementation at the whiteboard. I also now know more about how Groovy is implemented thanks to James Strachan. Dan Sugalski and Larry Wall's expositions of Perl internals and the Parrot VM were fascinating and at times, mind warping.
Obviously, I share Tim Bray's belief that dynamic languages are a hot area. There are literally dozens available for the JVM right now.
Obviously, I am biased in favour of Jython as a general purpose "glue" language for programming on the JVM. If you want to take my advice on board wholesale, get into Jython. If you don't want to go that far, get into *a* dynamic language for the JVM - any dynamic language is better than no dynamic language.
In my opinion, dynamic languages are the key to productivity, flexibility and evolvability of application-level programming on the JVM - especially in the integration space. (Psssssst: every time you use a JAR/CLASS you don't control, you have yourself an integration problem:-)
Do your Java productivity a favor - catch the wave.