Common Lisps exception mechanism is indeed out of this world, but that isn't something that has been implemented in any other language that I know of (not even Clojure) and you have to pay a fortune to get a CL system that works cross-platform with things like threading or a FI that allows lisp callbacks from C code. Java has supported both since forever (and its java.util.concurrent namespace means any old Java programmer has access to all sorts of really advanced non-blocking data structures, including a ConcurrentSkipListMap and an AtomicInteger) and for most people, for almost all tasks, that makes Java better. And for Java you need an IDE.