By the way, the following was just posted to the Clojure mailing list by Baishampayan Ghose:http://java.sun.com/developer/technical ... index.html
It's an article about features of JDK7 that are designed for dynamically typed languages. The article doesn't mention Clojure, but it does mention Armed Bear Common Lisp, Groovy, Jython, JRuby and something called Yoix that I've never heard of.
The Summary says:
Over the years, the JVM has been host to a growing number of languages, including implementations of dynamically typed languages such as Ruby and Python. Support for dynamically typed languages in the JVM is very attractive to application developers who build applications in these languages. That's because dynamic typing gives developers a lot of flexibility and the JVM delivers a lot of execution efficiency.
However, implementers of compilers for dynamically typed languages have found it difficult to meet the JVM bytecode requirements for method invocation. JSR 292 addresses that problem by providing a new bytecode, invokedynamic, and a new linkage mechanism based on method handles. Also being investigated for inclusion in JSR 292 is interface injection, the ability to modify classes at runtime so that they can implement new interfaces.