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From David Smith <d...@cornell.edu>
Subject Re: Classloader Concept
Date Tue, 24 Apr 2007 19:51:38 GMT
My experience has been the reverse -- shared/lib is usually disabled and 
not working, common/lib is used most of the time.

The difference between the two is common/lib is visible to both tomcat 
internals and the webapps.  That's why we put the db drivers in there 
for container managed connection pooling.   Shared/lib is only visible 
to the webapps -- tomcat internals can't see or access it.

--David

Luis Rivera wrote:

>   Hi,
>
> Just as a comment. I use the shared classloader by using the shared 
> folder
> to avoid loading multiple times my shared libraries (for jni use). I 
> am not
> sure what is the difference with the common/lib classloader, but it 
> did not
> work when I used that one.
>
> --Luis R.
>
> On 4/24/07, David Delbecq <delbd+jakarta@oma.be> wrote:
>
>>
>> Sorry Leon but you are wrong.
>> What Thomas looks for is common/lib, not server/lib
>> according to
>> http://tomcat.apache.org/tomcat-5.5-doc/class-loader-howto.html it's
>> common/lib that is loaded in common classloader. server/lib is loaded in
>> catalina classloader which is not visible for webapps.
>>
>>
>> To answer Thomas, yes, classes in common/lib get loaded only once in
>> permgen. The problem of loading classes in common/lib is that they get
>> shared. If some webapp call some static setter in JAF or JavaMail (to
>> set a resolver of any kind) this one will be used by all running
>> webapps. This can lead to curious bugs you might take a lot of time to
>> solve.
>>
>>
>> En l'instant précis du 24/04/07 10:42, Leon Rosenberg s'exprimait en ces
>> termes:
>> > i thinks its server/lib you are looking for (or common/endorsed) but
>> > i'm not sure whether java mail has some static fields which will be
>> > screwed by sharing them among all apps.
>> >
>> > leon
>> >
>> >
>> > On 4/24/07, Thomas Papke <tp@thopap.de> wrote:
>> >> I need some help to the classloader concept of tomcat... (version 
>> 5.5.)
>> >>
>> >> Our Tomcat has about 60 webapps running - right now every webapps 
>> have
>> >> in their Web/lib directory the libs for activation and java mail 
>> (among
>> >> other libs). As I understand, right now this libs are 60times loaded
>> >> into Permgen - if i will but them into the common/lib of tomcat - 
>> they
>> >> are loaded only once info permgen? Any problem to share 
>> activation.jar
>> >> and mail.jar inside common/lib for all webapps?
>> >>
>> >> Thanks a lot,
>> >>
>> >> Thomas
>> >>
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>> >>
>> >
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>>
>>
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>>
>


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