Should I still upload the patches here, I was just going to in a few
minutes, actaully?
> -----Original Message-----
> From: Scott Sanders [mailto:[EMAIL PROTECTED]]
> Sent: May 1, 2001 10:38 PM
> To: [EMAIL PROTECTED]
> Subject: Re: Bad classloading in Digester
>
>
> Done in Digester in commons. Thanks for the heads up Colin.
>
> Scott
>
> Craig R. McClanahan wrote:
>
> >
> > On Tue, 1 May 2001, Scott Sanders wrote:
> >
> >
> >> I can apply the patch to the code in
> jakarta-commons-sandbox as well.
> >>
> >> I would assume that a dependency on JDK 1.2 is not a
> problem. Someone
> >> will speak up if it is not.
> >>
> >
> >
> > No, it's not a problem. Struts requires 1.2 or later.
> >
> >
> >> Scott
> >>
> >
> >
> > Cragi
> >
> >
> >
> >> Colin Sampaleanu wrote:
> >>
> >>
> >>> There was never any reply to this message (below) I sent
> a few months ago
> >>> about a problem with the method used by the Digestor for
> class loading.
> >>>
> >>> In a number of places, it uses the old style
> >>> class.forName(name);
> >>> instead of the proper
> >>> Thread.getCurrentThread.getContextClassLoader.loadClass(name);
> >>>
> >>> The second form is _much_ preferred to the first, because
> the first will
> >>> potentially fail in any situation where there are
> multiple classloaders (one
> >>> owning the other), and the Digester is used in code loaded by both
> >>> classloaders (please see my original message for more details).
> >>>
> >>> This kind of situation is very common any time you have
> something like a
> >>> server (web, etc.) with containers in it, each container
> having its own
> >>> classloader associated with it in order to handle code
> visibility and
> >>> versioning. Using the digester in this situation is not
> possible without
> >>> modifying the code to use the second form.
> >>>
> >>> I am quite willing and able to upload patches to 4
> digester files to fix
> >>> this, assuming they will be checked in by somebody. The
> only implication is
> >>> that the code will no longer run under JDK 1.1, but
> Struts already needs 1.2
> >>> in any case...
> >>>
> >>> For more details on classloading issues in Java, here are
> a couple of
> >>> excellent white papers:
> >>> Understanclind Class.forName();
> >>> http://www.develop.com/downloads/DynLoad.zip
> >>> Exploiting the Java Virtual Machine:
> >>> http://www.develop.com/downloads/DevWPJav.pdf
> >>>
> >>>
> >>>
> >>>
> >>>
> >>>> -----Original Message-----
> >>>> From: Colin Sampaleanu [mailto:[EMAIL PROTECTED]]
> >>>> Sent: February 22, 2001 10:06 PM
> >>>> To: '[EMAIL PROTECTED]'
> >>>> Subject: ClassLoader used in Digester
> >>>>
> >>>>
> >>>> We are currently using the digester in a server we build that
> >>>> uses custom
> >>>> classloaders for some containers within it, which load
> custom apps.
> >>>>
> >>>> We use the Digester in the server itself, and some of the
> >>>> apps being loaded
> >>>> in the containers also want to use the Digester. The problem
> >>>> is that when an
> >>>> app creates a Digester instance, it is created by the
> parent (system)
> >>>> classloader that loaded the server, since the server had
> >>>> already used the
> >>>> Digester and that classloader knows about it. When the
> >>>> Digester then does a
> >>>> Class.forName in one of its rules to create an object, it
> >>>> knows nothing
> >>>> about the container's ClassLoader and the classes within it.
> >>>> The class is
> >>>> only withing the app, and so can't be found.
> >>>>
> >>>> Is there any downside to changing the Digester to always use:
> >>>> Thread.getCurrentThread.getContextClassLoader.loadClass(name);
> >>>> instead of
> >>>> class.forName(name);
> >>>>
> >>>> The code would no longer work in JDK 1.1, but that is already
> >>>> the case...
> >>>>
> >>>
> >>
> >>
>
>
