[concurrency-interest] examples of parallel processing in j2ee web apps?

borderline_ocd-er javafreelancer at gmail.com
Sat Dec 13 14:41:12 EST 2008

hello list,

please, can you share with us any examples (real-world or otherwise)
of using the java.util.concurrency api for doing parallel processing
in a j2ee web app?

this article gives one possible use case:

"...many Web applications have a set of tasks that can take advantage
of multithreaded processing, such as building a Web page in response
to a user request that requires queries to different databases and
loading a combination of text and images..." [1]

but is that the best example?

if any of the following is to be believed, the parallel programming
paradigm doesn't apply to j2ee web apps.

"...most web applications already parallelize pretty obviously at the
request level...But after that, it's generally difficult to
parallelize: if your request looks like "add a record to the User
table, then read the list of current users and render them to the UI"
it's just not easy to figure out how to parallelize..." [2]

"...There is simply no need for [parallel computing] in the vast
majority of applications...." [3]

an mdb/jms approach is often suggested as a "best practice" for
concurrency in j2ee web apps [4]; the JSR 237 Work Manager API [5] is
a neat option too. i know that spawning custom threads in j2ee
containers is discouraged. but, of course, people are doing it anyway.
so, please can you share with us any ideas (success stories, or
caveats, or horror stories) for using the java.util.concurrency api
for doing parallel processing in j2ee web apps?

thanks in advance for your replies.

[1] http://www.informationweek.com/news/software/open_source/showArticle.jhtml?articleID=206800900
[2] http://guidewiredevelopment.wordpress.com/2008/10/03/dont-believe-the-hype/
[3] http://blogs.techrepublic.com.com/programming-and-development/?p=745
[4] http://www.javaworld.com/javaworld/jw-07-2003/jw-0718-mdb.html?page=1
[5] http://www.jcp.org/en/jsr/detail?id=237

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