title: Performance: Creating an ArrayList from HashMap.values()
body: <p>Question is how much it costs to create an ArrayList from a HashMap.values() Collection? Or creating the values Collection alone?
  Assuming Map.size() > 100k.
  Objects could also be held in ArrayList (instead of HashMap) all the time which has implications in other parts (modifications of elements, easy by key).
  The ArrayList is used to iterate over every n-th element. (That's why the values collection can't be used directly). No modifications are done during the iteration.</p>