As an industry, we often under-prize developer productivity. Stu Halloway has found languages like Ruby and Lisp to be very productive. A few years ago he set out to do a comparison of 4 languages on the JVM and he found Clojure. Clojure is known for its simplicity, power, and concurrency capability. Halloway says that Java developers who are used to complexities in the platform have trouble realizing how certain aspects of development can be greatly simplified by newer languages like Clojure.
Stuart Halloway is the CEO and co-founder of Relevance, Inc., a Java, Spring, Hibernate, and Ruby on Rails shop. However, in the last 18 months, Halloway has been spending most of his time programming in Clojure. He is the author of several books including Programming Clojure, Rails for Java Developers, and Component Development for the Java Platform.