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Java / Map and its implementations

Why is ConcurrentHashMap faster than Hashtable in Java?

ConcurrentHashMap divides the whole map into different segments and locks only a particular segment during the update operation, instead of Hashtable, which locks whole Map.

The ConcurrentHashMap also provides lock-free read, which is not possible in Hashtable. ConcurrentHashMap is faster than Hashtable, especially when a number of the reader is more than the number of writers.

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Set and its implementations

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