I agree with Bruce, and dissagree with Sam. I think that JRuby is crucial. It isn’t crucial from “does ODEO care”, but it is from “will it be adopted widely”.
Java is not a language, it is a platform. Many companies have a lot of investment in this platform. The JVM itself is pretty darn good. It can out perform a lot of C++ code (as it isn’t compiled for the lowest common denominator), and there are lot of great tools for debugging, scaling, yada yada.
So many of our clients are invested in this platform that it is hard to move over to Ruby. This is why Groovy got a lot of buzz at the beginning. It allowed you to get to a dynamic through the back door. It was the glue for the VM.
Many people would much prefer Ruby thought of course, and having JRuby is a huge asset. Now I can use it at large clients, it can work with the Java world in a nicer way than web services or Web services. rabble from Odeo complained about the libraries. Now you have a choice of easily using a Java library that may be superior for what you are doing, and mixing and matching.
If I want to write a quick script I would much prefer writing Foo.new on a Java class and start using it compared to using darn web services :)
If Ruby is then on the JVM it will grow at a different level. It will also give you a lot more choices for libraries.
The best of all worlds. VMs are a nice abstraction. While we are talking about YARV and such we have a great VM on the other side of the fence. Rubys runtime is so darn poor, that running a top the well engineered JVMs from Sun, IBM, JRockit, …. is a great thing. It doesn’t mean that it is the only choice for Ruby, but its a great tool in the box.
I hope it can happen. JRuby is around 90% of the way, and needs a bit of help.