Which Java Collections are synchronized(thread safe), which are not?

Thread safe Collections –

1. ConcurrentHashMap

Thread safe without having to synchronize the whole map
Very fast reads while write is done with a lock
No locking at the object level
Uses multitude of locks.

2. SynchronizedHashMap

Object level synchronization
Both read and writes acquire a lock
Locking the collection has a performance drawback
May cause contention

3. Vector

4. HashTable

5. CopyOnWriteArrayList

6. CopyOnWriteArraySet

7. Stack

Rest all are not thread safe