simple MT in rhino/nashorn

counter.coffee

Mutex = java.util.concurrent.locks.ReentrantLock
Thread = java.lang.Thread
mutex = new Mutex
sum = 0

adder = (c) ->
  -> while c > 0
      c -= 1
      mutex.lock()
      sum += 1
      mutex.unlock()

newThread = (func, name) ->
  new Thread(->
    print "thread " + name + " started"
    func()
    print "thread " + name + " ended"
  )

threads = ( newThread(adder(t), "t" + t) for t in [1, 10, 100, 1000, 10000, 100000, 1000000] )
t.start() for t in threads
t.join() for t in threads

print "sum = " + sum