public static <T> NavigableSet<T> synchronizedNavigableSet (NavigableSet<T> s)

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

It is imperative that the user manually synchronize on the returned navigable set when traversing it, or any of its subSet, headSet, or tailSet views, via Iterator, Spliterator or Stream:

  NavigableSet s = Collections.synchronizedNavigableSet(new TreeSet());
      ...
  synchronized (s) {
      Iterator i = s.iterator(); // Must be in the synchronized block
      while (i.hasNext())
          foo(i.next());
  }
 

or:

  NavigableSet s = Collections.synchronizedNavigableSet(new TreeSet());
  NavigableSet s2 = s.headSet(foo, true);
      ...
  synchronized (s) {  // Note: s, not s2!!!
      Iterator i = s2.iterator(); // Must be in the synchronized block
      while (i.hasNext())
          foo(i.next());
  }
 

Failure to follow this advice may result in non-deterministic behavior.

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

Parameters:

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

Returns:  a synchronized view of the specified navigable set

Since:  1.8