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From "Steve Loughran" <stev...@iseran.com>
Subject Re: [Bug 1146] New - javax packages for JAXP cannot be overridden
Date Thu, 29 Mar 2001 23:41:14 GMT

----- Original Message -----
From: <bugzilla@apache.org>
To: <ant-dev@jakarta.apache.org>
Sent: Wednesday, March 28, 2001 18:50
Subject: [Bug 1146] New - javax packages for JAXP cannot be overridden


> http://nagoya.apache.org/bugzilla/show_bug.cgi?id=1146
>
> +
+===========================================================================
=+
> + | javax packages for JAXP cannot be overridden
|

> + |                              DESCRIPTION
|
> + Assume a task description roughly like this:
> + <java classname="MyClass">
> +   <classpath>
> +     <pathelement location="./jaxp.jar"/>
> +     <pathelement location="./crimson.jar"/>
> +   </classpath>
> + </java>
> +
> + where the JAXP and Crimson jars are NOT the same ones as distributed
with ant.
> +
> + What will happen here is that unless you fork the JVM, there is no way
to
> + override a javax.* class. This leads to some of the classes in this case
being
> + loaded by the AntClassLoader, and some of the classes being loaded by
the system
> + class loader. This isn't a problem unless you're using different
versions.
> +
> + The problem is most severe with JAXP, since it's the only thing which is
part of
> + the ant distribution's system javax.* namespace, but the same general
problem
> + takes place.

I am getting worn thin by jaxp related grief, of which ant is usually a
minor issue compared to the requirements of getting code to consistently
deploy to the various web servers out there. I've reached the point today
where my server side installation process (ant, of course) is dropping in
forcibly unsealed versions of crimson and jaxp into the server homes. This
bug report and Jim Stearns' classpath problems are all symptoms of the same
issue.


> + Finally, since javax.xml is the only thing for now for which there is no
> + reasonable workaround (aside from forking), javax.xml could be
special-cased
> + inside the AntClassLoader.

I do hate ugly one off hacks, but Jaxp is a uniform source of classloader
trouble.  Something needs to be done about it above and beyond any ant
fixes.

-steve


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