title: synchronizedCollection and contains--do I need to synchronize manually?
body: <p>I'm using Collections.synchronizedCollection in Java to protect a Set that I know is getting accessed concurrently by many threads.  The Java API warns:</p>
  
  <p>" It is imperative that the user manually synchronize on the returned collection when iterating over it:</p>
  
  <pre><code>Collection c = Collections.synchronizedCollection(myCollection);
       ...
    synchronized(c) {
        Iterator i = c.iterator(); // Must be in the synchronized block
        while (i.hasNext())
           foo(i.next());
    }
  </code></pre>
  
  <p>"</p>
  
  <p>If I use <code>c.contains(obj)</code>, is that thread-safe?  Internally, obviously, this is iterating over the Collection and seeing if any of the objects in it are equal to obj.  My instinct is to assume that this is probably synchronized (it would seem to be a major failing if not), but given previous pains with synchronization, it seems wise to double-check, and a Google search for answers on this hasn't turned up anything.</p>