Groovy or JRuby?

Originally published 24 Mar 2007

Which dynamic programming language should I introduce to a group of relatively young, inexperienced Java developers? The choice is between Groovy and JRuby.

Ruby and particularly Ruby on Rails has been hot for awhile now. Ruby in the enterprise is becoming more accepted. As Martin Fowler pointed out nearly a year ago in this blog entry , some top minds in our field including Bruce Tate, Justin Gehtland, and Stuart Halloway have moved Beyond Java . Even one of my old mentors, Mike Gaffney , has repeatedly told me to bail on Java. But I agree with Scott Davis as he points out in this podcast , Java is not dead.

The growing acceptance of Ruby is a strong reason to consider JRuby. Being able to run Ruby on Rails apps on the JVM is very appealing. But remember the context of the decision here. We're talking about a group of developers whose only development language has been Java, and whose projects for the foreseeable future will run on the Java platform. Groovy wins in this context.

There are lots of reasons to get excited about Groovy. It too runs on the ever-improving JVM. In fact, it was the first scripting language officially approved by Sun to run on the JVM. It can be compiled to byte code or run in script form. The interoperability is fantastic. Developers can still use Java, its tools and familiar libraries such as Spring and Hibernate , where appropriate, and mix in Groovy, where that is more appropriate.

But what really makes this decision easy is the similarity in language syntax. You can take a snippet of Java code, drop it into a Groovy file, and it will nearly work. Then, you can take that snippet and start making use of Groovy language improvements such as closures to make the code more readable and intention revealing .

So the decision is easy here. Take the seamless step forward and introduce Groovy.