public static <T> Set<T> synchronizedSet (Set<T> s)

Returns a synchronized (thread-safe) set backed by the specified set. In order to guarantee serial access, it is critical that all access to the backing set is accomplished through the returned set.

It is imperative that the user manually synchronize on the returned collection when traversing it via Iterator, Spliterator or Stream:

  Set s = Collections.synchronizedSet(new HashSet());
  synchronized (s) {
      Iterator i = s.iterator(); // Must be in the synchronized block
      while (i.hasNext())
Failure to follow this advice may result in non-deterministic behavior.

The returned set will be serializable if the specified set is serializable.

<T>    the class of the objects in the set
s    the set to be "wrapped" in a synchronized set.

Returns:  a synchronized view of the specified set.