Testing garbage collection of keywords

core.clj

(ns leak-test.core
  (:gen-class))

(def alphanumerics (concat (map char (range (int \A) (inc (int \Z))))
                           (range 0 10)))

(defn random-alphanumeric-string [len]
  "Generates a pseudo-random alphanumeric string"
  (apply str (repeatedly len #(rand-nth alphanumerics))))

(defn run-op [op secs]
  (let [start (System/nanoTime)]
    (while (< (/ (- (System/nanoTime) start) 1e9) secs)
      (op))))

;; running on repl: (run-op #(keyword (random-alphanumeric-string 10) (random-alphanumeric-string 10)) 1000)