[opencms-dev] Different version jars in lib folder

Mon Apr 18 07:12:24 CEST 2011

Hi,

one thing you could try: Run grep -r XIncludeAwareParserConfiguration
WEB-INF/lib/ to see if there are any other jars that have the xerces
classes inside.

Regards
Florian

Am 17.04.2011 13:17, schrieb Paul-Inge Flakstad:
> Hi again,
> 
> While this is (probably) not an OpenCms issue, I'm hoping someone can help me.
> 
> I have 3 OpenCms instances on my Tomcat, all use
> - xml-apis-2.9.1.jar
> - xercesImpl-2.9.1.jar
> 
> When I (re)start Tomcat, no problems. But when I do a hot redeploy of one of the OpenCms instances, a JSP I wrote (it parses an XML) throws this:
> java.lang.ClassCastException: org.apache.xerces.parsers.XIncludeAwareParserConfiguration cannot be cast to org.apache.xerces.xni.parser.XMLParserConfiguration: null
> com.sun.org.apache.xpath.internal.jaxp.XPathExpressionImpl.evaluate(XPathExpressionImpl.java:294)
> ...
> 
> Does anyone have ideas about why this is happening???
> 
> I thought this had to be due to conflicting versions of xerces, so in order to find my relevant libraries, I ran this (standing in ${TOMCAT_HOME}): 
> find . -name *xml-apis*
> and
> find . -name *xerces*
> 
> Only the libraries in the OpenCms webapps' lib/ folders (xml-apis-2.9.1.jar and xercesImpl-2.9.1.jar) are found. So, as far as I can tell, there is no conflict..! (Unless there are other libraries I should also check for differing versions?)
> 
> I would very much appreciate _any_ help - I've read everything I could find online, but can't get to the bottom of this... :(
> 
> Best regards,
> Paul
> 
> ________________________________________
> Fra: opencms-dev-bounces at opencms.org [opencms-dev-bounces at opencms.org] på vegne av Paul-Inge Flakstad [flakstad at npolar.no]
> Sendt: 15. april 2011 17:12
> Til: The OpenCms mailing list
> Emne: Re: [opencms-dev] Different version jars in lib folder
> 
> Update:
> 
> Confirmed that redeployment of the particular OpenCms webapp
> causes ClassCastExceptions to re-appear.
> 
> Paul
> 
>> -----Original Message-----
>> From: opencms-dev-bounces at opencms.org
>> [mailto:opencms-dev-bounces at opencms.org] On Behalf Of
>> Paul-Inge Flakstad
>> Sent: 15. april 2011 11:59
>> To: The OpenCms mailing list
>> Subject: Re: [opencms-dev] Different version jars in lib folder
>>
>> Hi again Achim,
>>
>> I should clearify that it isn't Tomcat that's throwing
>> exceptions around, it's a JSP I wrote that's parsing XML
>> files.
>>
>> The JSP is fine until [something] happens (possibly a redeploy
>> of the OpenCms webapp it resides in), then it starts throwing
>> ClassCastExceptions. The first time I experienced this, I
>> found differing jars in the lib/ folder of the OpenCms webapp.
>> I took care of this, and thought that would be the end of it.
>> This time, however, I cannot seem to find any "version
>> conflict".
>>
>> This is the reason I asked if different versions of a library
>> can cause conflict when the versions reside in two different
>> webapp/WEB-INF/lib folders/. I'm not sure if you noticed in
>> my first e-mail that they were _different_ webapps?
>> webapp_one/WEB-INF/lib/mylibrary-v1.0.jar  <-- one webapp
>> webapp_two/WEB-INF/lib/mylibrary-v2.0.jar  <-- another webapp
>>
>> I have 3 OpenCms instances running on the same Tomcat, they're
>> version 7.5.2 and 7.5.3 (so not a huge difference). I
>> restarted Tomcat last night, and everything was fine after
>> that, but I don't know what will happen when I redeploy the
>> webapp.
>>
>> I'll have a look at the link you gave me. Maybe I can make
>> sense of things.
>>
>> Thanks for your time and help, Achim - much appreciated! :)
>>
>> Cheers,
>> Paul
>>
>>> -----Original Message-----
>>> From: opencms-dev-bounces at opencms.org
>>> [mailto:opencms-dev-bounces at opencms.org] On Behalf Of Achim
>> Westermann
>>> Sent: 15. april 2011 10:10
>>> To: The OpenCms mailing list
>>> Subject: Re: [opencms-dev] Different version jars in lib folder
>>>
>>> Hi Paul,
>>>
>>>> You're absolutely right, and memory serves you well - they
>>> were 334 bytes indeed.
>>>
>>> Uuuuh.... Yesssss!
>>>
>>>>  From what you say, I gather it's risky to have different
>>> versions of OpenCms on the same Tomcat, then? (Since they may
>>> employ different version jars, which could cause conflict?)
>>>
>>> I'd consider it a bug if tomcat runs into Classloading errors
>>> if several
>>> OpenCms versions are deployed to different webapplications.
>>> But I am not
>>> sure now if there might be a special case where this might
>>> happen. The
>>> mechanism of classloading is explained here:
>>> http://tomcat.apache.org/tomcat-6.0-doc/class-loader-howto.html
>>>
>>> HTH,
>>> Achim
>>>
>>>> Cheers,
>>>> Paul
>>>>
>>>>> -----Original Message-----
>>>>> From: opencms-dev-bounces at opencms.org
>>>>> [mailto:opencms-dev-bounces at opencms.org] On Behalf Of
>>> Achim Westermann
>>>>> Sent: 14. april 2011 22:41
>>>>> To: The OpenCms mailing list
>>>>> Subject: Re: [opencms-dev] Different version jars in lib folder
>>>>>
>>>>> Hi Paul,
>>>>>
>>>>>> For example, all of these:
>>>>>> lucene-core-1.9.1.jar
>>>>>> lucene-core-2.1.0.jar
>>>>>> lucene-core-2.2.0.jar
>>>>>> lucene-core-2.3.1.jar
>>>>>> lucene-core-2.3.2.jar
>>>>>> lucene-core-2.4.1.jar
>>>>>
>>>>> Most often this is the case for OpenCms installations that have
>>>>> undergone at least one update. The setup routine will
>>>>> overwrite previous
>>>>> libraries with an empty jar file (size something like 334
>>>>> bytes, don't
>>>>> have this in memory) because in the past deletion of jar
>>> files failed
>>>>> under some circumstances. It's OK to delete all the tiny
>> jar files.
>>>>>
>>>>>> (Most of the commons-xxx jars, and a bunch of others as
>>>>> well, are also
>>>>>> present in multiple versions.)
>>>>>> What could be the cause of all these multiple versions? Is
>>>>> it safe to
>>>>>> delete the older versions and just keep the most recent?
>>>>>> On a side-note:
>>>>>> Can two different versions of the "same" jar cause
>>>>> conflicts, if they
>>>>>> reside in the separate webapps' lib folder?
>>>>>> For example:
>>>>>> webapp_one/WEB-INF/lib/mylibrary-v1.0.jar
>>>>>> webapp_two/WEB-INF/lib/mylibrary-v2.0.jar
>>>>>
>>>>> Indeed this can cause ClassCastExceptions. It's a matter
>> of luck in
>>>>> which order the jar files are loaded by the
>> ClassLoaders. Duplicate
>>>>> non-empty jar files have to be deleted as you described.
>>>>>
>>>>> HTH,
>>>>>
>>>>> Achim
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> This mail is sent to you from the opencms-dev mailing list
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>>>>> please visit
>>>>> http://lists.opencms.org/mailman/listinfo/opencms-dev
>>>>>
>>>>
>>>> _______________________________________________
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>>>
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>>
>> _______________________________________________
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> 
> _______________________________________________
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> 
> _______________________________________________
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