Difference between Hashtable and ConcurrentHashMap

Question

Can someone elaborate this line briefly?

“In Summary ConcurrentHashMap only locked certain portion of Map while Hashtable lock full map while doing iteration”

http://stackoverflow.com/q/12646404/18157 – Jim Garrison Mar 12 '16 at 07:46 — Jim Garrison, Mar 12 '16 at 07:46

score 0 · Accepted Answer · answered Mar 12 '16 at 07:47

The reason is scalability. ConcurrentHashMap divides the map in parts and locks them individually. So multiple threads can access those different parts simultaneously. But a given segment is synchronized.

In essence it's about partial locking of the collection versus full locking.

Read this for more.

Difference between Hashtable and ConcurrentHashMap

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