Comments on: Concurrency Pattern: Concurrent Set implementations in Java 6 http://dhruba.name/2009/08/05/concurrent-set-implementations-in-java-6/ Maximum Zeal ~ Emphatic prose on indulged fascinations Tue, 13 Mar 2012 03:08:43 +0000 hourly 1 http://wordpress.org/?v=3.2.1 By: Dhruba Bandopadhyay http://dhruba.name/2009/08/05/concurrent-set-implementations-in-java-6/comment-page-1/#comment-32603 Dhruba Bandopadhyay Wed, 21 Sep 2011 21:32:47 +0000 http://dhruba.name/?p=1117#comment-32603 Hi Semyon! That is an excellent point. And well done for profiling. So few people do it these days - everyone is always complaining they have no time. I do miss the more interesting work along with you guys. So, yes, I agree. The key point about Cliff Click's collections as has often been mentioned by Doug Lea himself on the concurrency mailing list (http://goo.gl/ATpmV as an example) is that they are better for certain usage patterns with the JDK equivalents being better for others. It's amazing how many people don't know about the trick in this post. This must be one of the most popular posts on the blog. The entire codebase I'm working with at work is using CopyOnWriteArraySet as a concurrent set everywhere. Imagine that! :-) Luckily most uses of Set for us are only to store listeners (observer pattern). I'm looking forward also to the new ConcurrentHashMap that is upcoming in Java 8 (http://goo.gl/2cHFJ). Check it out! Hi Semyon! That is an excellent point. And well done for profiling. So few people do it these days – everyone is always complaining they have no time. I do miss the more interesting work along with you guys. So, yes, I agree. The key point about Cliff Click’s collections as has often been mentioned by Doug Lea himself on the concurrency mailing list (http://goo.gl/ATpmV as an example) is that they are better for certain usage patterns with the JDK equivalents being better for others.

It’s amazing how many people don’t know about the trick in this post. This must be one of the most popular posts on the blog. The entire codebase I’m working with at work is using CopyOnWriteArraySet as a concurrent set everywhere. Imagine that! :-) Luckily most uses of Set for us are only to store listeners (observer pattern). I’m looking forward also to the new ConcurrentHashMap that is upcoming in Java 8 (http://goo.gl/2cHFJ). Check it out!

]]> By: Semyon Ch http://dhruba.name/2009/08/05/concurrent-set-implementations-in-java-6/comment-page-1/#comment-32549 Semyon Ch Tue, 20 Sep 2011 19:12:25 +0000 http://dhruba.name/?p=1117#comment-32549 NonBlockingHashSet is good for "add" but it is vey slow in case of iteration. Profiling (JProfiler7) showes that iteration over NonBlockingHashSet around 10 times slower than iteration over the set built on ConcurrentHashMap. We replaced NonBlockingHashSet with the latter one. NonBlockingHashSet is good for “add” but it is vey slow in case of iteration. Profiling (JProfiler7) showes that iteration over NonBlockingHashSet around 10 times slower than iteration over the set built on ConcurrentHashMap.
We replaced NonBlockingHashSet with the latter one.

]]> By: Dhruba Bandopadhyay http://dhruba.name/2009/08/05/concurrent-set-implementations-in-java-6/comment-page-1/#comment-32520 Dhruba Bandopadhyay Tue, 20 Sep 2011 07:02:01 +0000 http://dhruba.name/?p=1117#comment-32520 Thanks Semyon! I'm really glad I could help. And when readers provide positive feedback it makes all the effort worthwhile. Don't forget - if you have the option to use the NonBlockingHashSet then use it instead. It will be faster than jdk for most use cases. Thanks Semyon! I’m really glad I could help. And when readers provide positive feedback it makes all the effort worthwhile. Don’t forget – if you have the option to use the NonBlockingHashSet then use it instead. It will be faster than jdk for most use cases.

]]> By: Semyon Ch http://dhruba.name/2009/08/05/concurrent-set-implementations-in-java-6/comment-page-1/#comment-32486 Semyon Ch Mon, 19 Sep 2011 14:02:54 +0000 http://dhruba.name/?p=1117#comment-32486 Hello Dhruba! 7th result in google search on query "ConcurrentHashSet"! On the first page! Of course, your blog was the first link I navigated to as I was sure there would be a clear answer! Hello Dhruba!
7th result in google search on query “ConcurrentHashSet”!
On the first page!
Of course, your blog was the first link I navigated to as I was sure there would be a clear answer!

]]> By: JamesD http://dhruba.name/2009/08/05/concurrent-set-implementations-in-java-6/comment-page-1/#comment-24334 JamesD Thu, 21 Apr 2011 18:02:15 +0000 http://dhruba.name/?p=1117#comment-24334 Awesome stuff. Thanks! Awesome stuff. Thanks!

]]> By: Pip http://dhruba.name/2009/08/05/concurrent-set-implementations-in-java-6/comment-page-1/#comment-12785 Pip Sat, 06 Mar 2010 19:24:38 +0000 http://dhruba.name/?p=1117#comment-12785 very nice! thanks. very nice! thanks.

]]> By: Siggy http://dhruba.name/2009/08/05/concurrent-set-implementations-in-java-6/comment-page-1/#comment-12710 Siggy Tue, 02 Mar 2010 18:12:52 +0000 http://dhruba.name/?p=1117#comment-12710 Big thanks; a very useful method. Big thanks; a very useful method.

]]> By: Evgeny http://dhruba.name/2009/08/05/concurrent-set-implementations-in-java-6/comment-page-1/#comment-12456 Evgeny Thu, 18 Feb 2010 14:39:41 +0000 http://dhruba.name/?p=1117#comment-12456 thanks for your post. That's exactly what I've been looking for thanks for your post. That’s exactly what I’ve been looking for

]]> By: Paul http://dhruba.name/2009/08/05/concurrent-set-implementations-in-java-6/comment-page-1/#comment-12246 Paul Tue, 09 Feb 2010 04:22:34 +0000 http://dhruba.name/?p=1117#comment-12246 Thanks for this list. I find it very useful. :) Thanks for this list. I find it very useful. :)

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