which java collections are synchronized(thread-safe), which are not?

Question

Which java collections are synchronized, which are not?

Answer 1

Legacy collections like Vector and Hashtable are synchronized. Collections that are synchronized by Collections.synchronized<collectionname>. Concurrent collections like CopyOnWriteArrayList, CopyOnWritearraySet,ConcurrentLinkedQueue, ConcurrentSkipListMap, ConcurrentHashMap,BlockingQueue are synchronized.

ArrayList, LinkedList, HashMap, HashSet, Treemap, Treeset are not synchronized.

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