[Fwd: Re: [jdom-interest] OutOfMemoryError]

[Paul Hunnisett]

Yes, I do...


(You probably want to post this to the list...)

At 2006-05-09 18:01, Paul Hunnisett wrote:
>Content-Transfer-Encoding: 8bit
>
>OK, I've managed to get a memory profiler running on my code.
>
>The first thing I discovered was that in this portlet the 
>javax.xml.transform.Transformer which was being allocated huge 
>amounts of memory.  The same object in other portlets was getting 
>much more sensible levels of memory.
>
>I then changed the code so that the xml that was passed into the 
>transformer was a String.  The portlet was still making a web 
>service call and was still converting the result to a JDOM.
>
>Same result.
>
>I then changed the code so that the transform got a string and no 
>web service call was made - so at no point did I have a dom in 
>memory: standard or JDOM.  The transformer now has much more 
>sensible levels of memory.
>
>I don;t understand why the transformer should be in anyway affected 
>by whether there is a dom in memory, but it seems to be.
>
>Is anyone able to shed any light on what my next move should be?
>
>Cheers
>
>Paul Hunnisett
>
>Mattias Jiderhamn wrote:
>>I assume you are talking about JUnit tests. You could execute the 
>>tests "manually" in a loop. Look at the TestRunner classes in JUnit.
>>(Though I suppose you could also just do what you do inside the 
>>test in a loop, unless it depends on dependency injection or something)
>>At 2006-05-09 12:37, Paul Hunnisett wrote:
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>>>
>>>Possibly.  I have unit tests that test the calls to the web service.
>>>If you know a way of making unit tests run over and over in the 
>>>same VM then I can do that.  It seems likely to me that the 
>>>problem is either during the service call or the XSL transform - 
>>>since that's pretty much all I'm doing. If I can get my unit tests 
>>>to loop over then I can maybe some kind of idea if it's happening 
>>>there or the transform...
>>>
>>>Cheers
>>>
>>>Paul
>>>
>>>Mattias Jiderhamn wrote:
>>>>Can you reproduce the problem outside the container, in a 
>>>>standalone application?
>>>>At 2006-05-08 16:23, Paul Hunnisett wrote:
>>>>>Content-Transfer-Encoding: 8bit
>>>>>
>>>>>How do I determine whether it's heap or permgen?  All I get is: 
>>>>>java.lang.OutOfMemoryError
>>>>>
>>>>>I doubt it's an issue with redeploying in tomcat as this is 
>>>>>something we've done several times a day for the last year and 
>>>>>it's not like I'm redeploying this often now as the application 
>>>>>is complete - the only outstanding issue is this memory one...
>>>>>
>>>>>It does seem to be a cumulative problem.  I can make about 4 or 
>>>>>5 soap calls before it falls over...
>>>>>
>>>>>Cheers
>>>>>
>>>>>Paul
>>>>>
>>>>>Mattias Jiderhamn wrote:
>>>>>>At 2006-05-08 15:39, Paul Hunnisett wrote:
>>>>>>>I work on a university portal where our channels are developed 
>>>>>>>as portlets.
>>>>>>>
>>>>>>>I recently started a new portlet which would act as a client 
>>>>>>>to a Web service.  The WS returned a DOM which would then be 
>>>>>>>passed to an XSL transform.  I decided that this was a good 
>>>>>>>opportunity to test JDOM in anger and convert the returned DOM 
>>>>>>>in to JDOM before anything else happens to it.
>>>>>>>
>>>>>>>The problem is that after only a little interaction with the 
>>>>>>>portlet I get an OutOfMemoryError that brings down the whole 
>>>>>>>portal.  I'm confident that it's JDOM that causes this as we 
>>>>>>>have several other channels which do the same thing with 
>>>>>>>standard DOM and cause no such problems.
>>>>>>>
>>>>>>>All of the returned documents are small.
>>>>>>>
>>>>>>>My initial impression of JDOM is very good, but unless we can 
>>>>>>>fix this then it's not going to be an option for us.
>>>>>>>
>>>>>>>I've already tried increasing the VM memory allocation abd 
>>>>>>>still get the same problem - as well as grinding my workstation to a crawl!
>>>>>>Are you ouf of heap or PermGen?
>>>>>>What application server are you using? Tomcat has a well known 
>>>>>>leak of PermGen space when an application is redeployed over 
>>>>>>and over, which would be the case during development.
>>>>>>
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