Today's Question:  What are you most afraid of as a programmer?        GIVE A SHOUT

Technical Article => Programming =>  Java

Difference between ConcurrentHashMap and Hashtable

  sonic0002      2013-11-18 08:06:54      32,478    3    0

Both ConcurrentHashMap and Hashtable are Collection classes for storing key value pairs and they both provide fast element search with a supplied key. They have much in common. However, we will not discuss the similarities between them here, instead we will focus on the differences between them.

ConcurrentHashMap and Hashtable are both thread safe. But the mechanism for thread safe is different between them. Hashtable is synchronized, it utilizes the synchronization mechanism; while ConcurrentHashMap uses segmentation to lock the data, it uses concurrent locks operations for thread safety instead of synchronized.

Since ConcurrentHashMap introduced concept of segmentation , how large it becomes only certain part of it get locked to provide thread safety so many other readers can still access map without waiting for iteration to complete.

So if you want to store large amount of data in a multithreaded program, you should consider to choose ConcurrentHashMap.



Share on Facebook  Share on Twitter  Share on Google+  Share on Weibo  Share on Reddit  Share on Digg  Share on Tumblr    Delicious



hi [Reply]@ 2013-11-22 05:00:23




hi [Reply]@ 2013-11-25 21:57:33


Input Validation needed  [Reply]@ 2013-11-25 23:07:03


Input validation is needed for Nickname :)




iPhone becomes a brick

By sonic0002
A Chinese iPhone user was using iTunes to upgrade his system. The upgrade is 80% done and then Windows 10 starts automatic upgrade. The consequence is the iPhone becomes a brick.