Api is in a separate jar (api.jar) that is both in webapp & commons :
when I don't put it in commons, I get a NoClassDefFoundError from line (1) :
Class clazz = Class.forName(className);
I can't exclude it from webapp (WEB-INF/lib) as it is part of webapp with the
production implementation jar.
I need some way to force ClassLoading to search webapp first, even when it delegates a
class search to commons
ClassLoader. Perhaps they're is no solution...
Nico.
> Where is the JAR file that contains IExternalSystem?
>
> Quoting Nicolas De Loof <[EMAIL PROTECTED]>:
>
> > the webapp hasn't trouble to load ExternalSystemMockImpl. It uses reflexion
> > to do it from some configuration data that
> > is use to set implementation (production | mock).
> >
> > The problem is that the resulting object has to be casted to an interface
> > from the API : IExternalSystem:
> >
> > (1) Class clazz = Class.forName(className);
> > (2) return (IExternalSystem) clazz.newInstance();
> >
> > from webapp, I think IExternalSystem is loaded by webapp ClassLoader. As
> > ExternalSystemMockImpl is loaded from tomcat
> > "commons" ClassLoader, it doesn implements the IExternalSystem loaded by this
> > commons-ClassLoader, that cannot be casted
> > in IExternalSystem loaded by webapp-ClassLoader.
> >
> > I get a ClassCastException on line 2.
> >
> > Nico.
> >
> >
> >
> > > If ExternalSystemMockImpl is contained in a JAR file that's in
> > > $CATALINA_HOME/common/lib, I don't see why the app wouldn't be able to load
> > it.
> > > For example, I've got a JAR file for the Oracle JDBC driver in common/lib
> > and I
> > > can do the following just fine in a JSP:
> > >
> > > <%
> > > ClassLoader cl = getClass().getClassLoader();
> > > Class clazz = cl.loadClass("oracle.jdbc.OracleDriver");
> > > Object obj = clazz.newInstance();
> > > %>
> > >
> > > If there's code in the external JAR file that needs to make use of a
> > class
> > > loader, it should probably use the result of
> > > Thread.currentThread().getContextClassLoader(). Can you provide a little
> > more
> > > detail on how the app is using reflection to locate
> > ExternalSystemMockImpl?
> > >
> > > Quoting Nicolas De Loof <[EMAIL PROTECTED]>:
> > >
> > > > Hi all,
> > > >
> > > > I'm posting on Struts list because I know they're is lot's of J2EE
> > experts
> > > > here.
> > > >
> > > > I want to test my webapp on Tomcat, but it depends on some external
> > system.
> > > > I've got a jar that emulates it. When I
> > > > package it with the webapp (WEB-INF/lib) it works fine.
> > > >
> > > > I would like to test the webapp packaged without this emulator jar. I
> > tried
> > > > putting it in $TOMCAT/common/lib. I get a
> > > > ClassCastException. I think it comes from this :
> > > >
> > > > webapp requires the external API, let's say a class named
> > "ExternalSystem".
> > > > It is configured to search for an
> > > > implementation class named "ExternalSystemMockImpl" (using reflexion
> > API).
> > > >
> > > > Webapp classloader doesn't find it, and delegate class searh to it's
> > parent
> > > > classloader (tomcat ones). Parent
> > > > classloader finds the class from my emulator jar, run it and return
> > some
> > > > "MockResult" object, that implements
> > > > "ExternalResult" from the external API
> > > >
> > > > Calling webapp tries to cast resulting object to "ExternalResult", class
> > that
> > > > is visible to webapp classloader.
> > > >
> > > > Then my code is doing :
> > > >
> > > > ExternalResult result = (ExternalResult) obj;
> > > >
> > > > where obj is my MockResult instance, that implements ExternalResult
> > from
> > > > parent-Classloader, and casting it to a
> > > > webapp-Classloader ExternalResult fails !
> > > >
> > > >
> > > > How can I solve this ClasLoader conflict ?
> > > >
> > > > Nico.
> > >
> > > --
> > > Kris Schneider <mailto:[EMAIL PROTECTED]>
> > > D.O.Tech <http://www.dotech.com/>
>
> --
> Kris Schneider <mailto:[EMAIL PROTECTED]>
> D.O.Tech <http://www.dotech.com/>
>
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