is synchronized Collection's toArray() method synchronized?

Question

If I have a synchronized collection like this

Collection c = Collections.synchronizedCollection(myCollection);

javadoc for the synchronizedCollection mentiones that external iteration must be synchronized like this :

synchronized (c) {
 Iterator i = c.iterator();
 while (i.hasNext()) {
     process (i.next());
 }
}

Can I assume that c.toArray() is synchronized and therefore no changes to the collection will happen when the method executes?

Or do I need to synchronize it as well:

synchronized (c) {
  c.toArray();
}

Answer 1

From the Javadoc for synchronizedCollection:

Returns a synchronized (thread-safe) collection backed by the specified collection.

Thus, c.toArray() does not require any additional synchronization. SynchronizedCollection's toArray() method will do the locking for you. In essence, that's the whole point of synchronizedCollection().

If you want to confirm that this reading of the contract agrees with the actual implementation, see GrepCode.