Re: shared libraries - visibility issues - shared/lib, common/lib, etc

Hi Chris,

Here is the reference to the Tomcat documentation that explains how 
class loaders work in Tomcat, and the relationship between the different 
shared library directories :

http://tomcat.apache.org/tomcat-5.5-doc/class-loader-howto.html

This should help you understand the behaviour. Also note that if you 
have the same library at multiple locations but in *different versions* 
(for example Log4J), you might run into some unexpected behaviour.

Regards,
  Serge Huber.

chris markiewicz wrote:
> Hello.
>
> I have a handful of webapps which use a JAR that I created.  This JAR
> depends on a handful of other JARs, etc etc.  Essentially I want my webapps
> to be able to use this JAR - without putting the JAR into the individual
> webapps.
>
> I originally put my JAR and other related JARs into the shared/lib/
> directory - but my webapps could still not see my JAR.  I moved my JAR into
> common/lib/, and this improved things slightly - but it couldn't see some of
> its dependencies, so I moved them too.  Still getting some visibility errors
> though.
>
> Finally, I moved my JAR (but not its dependencies) into the lib/ directory
> of an individual webapp, and everything works perfectly.
>
>
> I've done some research and I read that the shared/lib/ directory is visible
> to the webapps, but not the container.  Additionally, the common/lib/
> directory is visible to webapps AND the container.
>
>
> I have several questions.  First, is the preceding paragraph (visibility of
> those directories) correct, within the context of Jahia?  
>
> Second, my error seems very clearly to be a visibility issue.  My current
> guess is that there is something in my shared/lib/ directory that needs to
> be in my common/lib directory.  Does this sound correct?  (Obviously this is
> something I can test - and I am testing, but moving jars is a slow process,
> involving a restart, etc).
>
> Finally, generally speaking, what is the common practice for the placement
> of these dependencies?
>
> Thanks for your time.
> Chris
>
>
>