For what it is worth, try using request.getSession(false) instead. You may
have been running into a situation where you were not synchronizing on a
unique object. I'm not sure which server you are using, but it may be
returning a new session object instance (not logical instance) when there is
an exclusive hold on the prior session instance.

My two cents,

Glenn

>From: "Kalra, Ashwani" <ashwani.kalra@(protected);
>Reply-To: An interest list for Sun Java Center J2EE Pattern Catalog
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>To: J2EEPATTERNS-INTEREST@(protected)
>Subject: concurrency problem
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>
>I am facing concurrency problem in following scenario.
>
>
>
>All our action classes call same stateful session bean . Each action
class obtains the reference from HTTPSession object and calls one and only
one business method.
>
>To prevent the concurrent access to this instance which occurs when user
immediately presses two links quickly in succession I am using the following
code block
>
>
>
>execute(...) //execute methods of Action class
>
>{
>
>.....
>
>.....
>
>//Obtain the session from Request.User will always be in session here
>
>session=request.getSession()
>
>Synchronised(session)
>
>{
>
>//call ejb's business method.
>
>}
>
>
>
>}
>
>However sometimes more than one thread is able to pass through, And I
get exception from Appserver. As 2 threads are not allowed for statefull
Session bean.
>
>Can there be problem in above code. Is it ok to synchronise on session
object.
>
>Thanks & Regds
> Ashwani
>
>Ext: 1860
>
>
>
>
>
>
>
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