I really love how well this works with Cider though, for Clojure projects. It even lets you jump to the definition of Java or Clojure files that live outside your current project, e.g. in third party libraries or even the Java standard library. Why, just today I jumped to the definition of java.time.Month because I had never actually seen a real live Java enum before. (Sure enough, it's defined with the keyword `enum`. Neat!) Cider has become essential to my Clojure workflow at work.