Hi Eddy,
can you please confirm that for these last tests you put the jpox
libraries outside the web application WEB-INF/lib dir?
You told me yesterday that you got an exception using regular JSP
too, is that not the case anymore?
Best regards,
Geert
On 12 Apr 2006, at 11:13, Eddy Young wrote:
Geert Bevin wrote:
Hi Eddy,
not that I recall. Care to expand on this?
Best regards,
Geert
Geert,
After our online conversation yesterday, I did some more tests to
try and pinpoint the exact source of the problem. I think I've
managed to establish that the problem is related to the RIFE
classloader in some way.
But first, here is some background information for the others on
the mailing list.
I am using JPOX, a JDO implementation, to persist objects to a
database. In JDO, JDOHelper.getPersistenceManagerFactory(Properties
properties) is used to instantiate the PersistenceManagerFactory
implementation that is specified in the properties (that is,
introspection is used to locate and instantiate the correct class).
In my tests, when that method is called from a console application
or a JSP page (RIFE not involved), no exception is thrown; all
classes are loaded and instantiated successfully. However, when the
same method is called from a RIFE Element, a LinkageError exception
is thrown for the Level class from the Log4j package. That
exception triggers a chain of other exceptions that prevent the
PersistenceManagerFactory from being instantiated.
After much fiddling around (until 2am to be exact), I tried
instantiating the PersistenceManagerFactory class with a
classloader specified. I called the variant method
JDOHelper.getPersistenceManagerFactory(<properties>,
<classloader>), passing 1) the current thread context classloader
and 2) the parent classloader of the current thread context
classloader.
In case 1) the classloader is the RIFE classloader. That caused the
LinkageError exception to be thrown.
In case 2) the classloader is the Catalina WebappClassloader (I am
using Tomcat), and with that, the PersistenceManagerFactory class
was instantiated successfully.
This is as far as I reached in my investigation. I wanted to share
this here in order to get your feedback on it. If you have
encountered this problem in a differnet scenario, please let me
know. As you rightly pointed out, such conflict errors are very
hard to trace, so I would be very grateful if you could help in any
way.
If my analysis is wrong (again!), I apologise; as I said, I stayed
up until quite late to try and sort this out.
Regards,
Eddy
--
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