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Message-ID: <005a01c334bd$35f3f6b0$0a00000a@BAMBAM>
From: "Guus Holshuijsen" <guus.holshuijsen@videtur.nl>
To: <tomcat-user@jakarta.apache.org>
Subject: ClassNotFoundException
Date: Tue, 17 Jun 2003 12:42:55 +0200
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Hi!

I am stuck with the following "challenge".

After some initial problems with my web application with regard to =
ClassNotFoundExceptions when trying to read blobs from a MySQL database =
which was caused by my lack of knowledge regarding the Tomcat class =
loading filosophy (which is explained very well in =
http://jakarta.apache.org/tomcat/tomcat-4.1-doc/class-loader-howto.html) =
I am stuck with the following:

I started out with a web application that was fully selfcontained i.e. =
it
did not use database or JNDI resources defined in the Tomcat container. =
So
there was a mysql-connector-java.jar in the WEB-INF/lib of the web
application and the classes were in WEB-INF/classes. While developing =
under
Forte4J (SunONE Studio update 1, Tomcat v4.0.1, NetBeans, Windows2000)
everything seemed to work fine. Then I deployed to a RedHat Linux 8.0 =
host
running Tomcat v4.0.3 and I got the ClassNotFoundException.

QUESTION:
Can somebody explain - in terms of class loading - why I get
the ClassNotFoundException when both the MySQL driver stuff and the web
application are in the same class loader context (at least they are =
there
from my point of view).

Then I changed to running Tomcat v4.1.24 both on W2000 and RH 8.0 (with =
JDK
1.4.0_01), I redesigned my web application to use the Tomcat filosophy =
regarding JNDI and database resources and I still got the =
ClassNotFoundException, that is until I found the documentation about =
class loading...

What I don't like much is that I have to move part of my web application =
code (the classes that are stored as blob in the database) into the =
container's common/lib directory. This causes deployment of my web =
application to be more difficult and makes my web application less =
portable.

Of course I did NOT read all of the Tomcat documentation, so I will not =
say that I know all about the different ways to configure a web =
application in Tomcat, but sometimes a few words in the right direction =
helps me to focus.

I'm off reading more of the Tomcat docs and hope for somebody out there =
to enlighten me ;-)=20

Regards,
Guus


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