Is Collections.syncronizedList effectively a vector?

Does Collections.syncronizedList(new ArrayList()) effectively makes the arrayList a vector? If no then what extra does it do? If yes then why was it introduced in the first place?

开发者_JAVA技巧

Thanks.

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It provides a synchronized view (a wrapper) of any list. The differences:

• you can make a synchronized view of any list implementation. A synchronized LinkedList is not a Vector.
• the original list is not synchronized - only the view is.

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1. It doesn't make a list something else, but wraps a List with something that looks like a list also, but contains no data except the wrapped list.
2. See 1.

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Collections.synchronizedList(...) wraps synchronized access to the underlying list, but still retains the underlying list's characteristics in other ways. So for example, if you wrap a LinkedList, the iterator() remove() will be an efficient operation. (The same operation on a Vector is O(n).)

So the wrapper is absolutely not the same as a Vector.