Re: Got the Issue

[Soumya Chatterjee]

Hi Michael,
 
This is really strange that read also needs to be synchronized and due to the performance / caching mechanism developers will get the nullpointerexception while reading it in multi threaded environment. 
 
Is our case, we need to create the DOM once and reads multiple times in a concurrent access. I think it may be worth implementing a higher level read-only(immutable) Data tree that reads only once from the DOM/SAX.
 
Thanks again for all the help.
Thanks,Soumya ChatterjeeTata Consultancy ServicesMailto: [EMAIL PROTECTED]Website: http://www.tcs.com____________________________________________Experience certainty. IT ServicesBusiness SolutionsOutsourcing____________________________________________ 




Michael Glavassevich <[EMAIL PROTECTED]> 
07/24/2007 09:57 AST

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Soumya Chatterjee <[EMAIL PROTECTED]>


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j-users@xerces.apache.org


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Re: Got the Issue


Hi Soumya,Xerces' DOM implementation isn't thread-safe. If you try to access thesame DOM instance from multiple threads without synchronizing it you'llrun into these problems. You either need to synchronize your code orcreate an instance of the DOM tree per thread. There's really no wayaround it.Thanks.Michael GlavassevichXML Parser DevelopmentIBM Toronto LabE-mail: [EMAIL PROTECTED]E-mail: [EMAIL PROTECTED]Soumya Chatterjee <[EMAIL PROTECTED]> wrote on 07/24/2007 09:42:08AM:> Hi Michael,>> I found out the response from you regarding the "xerces DOM> concurrent access" and I think it is the same as our application in> the case.  http://spteam-lists.blogspot.com/2007/04/re-xerces-dom-> concurrent-access-and.html>> By the way we were not getting the exception as frequently  in the> weblogic 7.1 ( JDK 1.3) when we are using the following Xerces.>> But we are getting the exception in case of weblogic 9.1 much more> frequently which uses JDK1.5 and different version of Xerces.>> Synchronization is not an option in this case because there is a> huge performance issue here. Please let me know if any way we can> get read of this problem without using the Synchronization  block.>> Thanks,> Soumya Chatterjee> Tata Consultancy Services> Mailto: [EMAIL PROTECTED]> Website: http://www.tcs.com> ____________________________________________> Experience certainty.        IT Services>                        Business Solutions>                        Outsourcing> ____________________________________________ForwardSourceID:NT00020C32 =====-----=====-----=====
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