testthreads.clj

(let [v (atom [0 0 0 0 0])
      threads (for [i (range 5)]
                (let [t (Thread.
                         (fn []
                           (dotimes [_ 1000] (swap! v update i inc))
                           ))]
                  (.start t)
                  t))]
  (doseq [t threads] (.join t))
  @v)

(let [v (volatile! [0 0 0 0 0])
      threads (for [i (range 5)]
                (let [t (Thread.
                         (fn []
                           (dotimes [_ 1000] (vswap! v update i inc))
                           ))]
                  (.start t)
                  t))]
  (doseq [t threads] (.join t))
  @v) 

(let [v (transient [0 0 0 0 0])
      threads (for [i (range 5)]
                (let [t (Thread.
                         (fn []
                           (dotimes [_ 1000] (assoc! v i (inc (get v i))))
                           ))]
                  (.start t)
                  t))]
  (doseq [t threads] #(.join t))
  (persistent! v))