Suppose you need inter-thread shared unordered Set of elements. Options are CopyOnWriteArraySet and ConcurrentHashMap-backed Set created by Collections.newSetFromMap(new ConcurrentHashMap<E, Boolean>()). Both are thread-safe, both are safe to iterate and do not throw ConcurrentModificationException, but unlike map-backed one, CopyOnWriteArraySet has O(n) complexity on mutation operations.
So the question is in which cases CopyOnWriteArraySet is really better?
Thanks in advance!
