This is probably unrelated, but since you seem stuck I will tell you about
an annoying issue that I have not yet investigated.  Hopefully this will
help you in some way.

My issue is I sometimes get an NPE when tomcat de-serializes a session.  (I
valid solution for me is just to turn this serialization between shutdowns
off...I just haven't got there yet)  I have an object that gets read from
the database and then gets eventually referenced by my session beans.  The
hashCode() method for my object is the ID field.  Even though I am quite
sure that no objects with the ID field as null are never part of my session,
on start up tomcat sporadically finds one in a serialized session and then
the de-serialization mechanism throws an NPE when tomcat starts up.  

I am a newbie to session serialization, and so it is possible there is a
"secret" I don't know.  Still, maybe this anecdote will help you.

Mark

> -----Original Message-----
> From: Shapira, Yoav [mailto:[EMAIL PROTECTED] 
> Sent: Wednesday, November 10, 2004 4:14 PM
> To: Tomcat Users List
> Subject: RE: class loader problem?
> 
> 
> 
> Hi,
> Thanks for posting, but I think you're on your own.  I 
> personally am not going to waste time looking into a class 
> removed by another project ;) Maybe someone else is curious, 
> or someone on the FOP list.
> 
> Yoav Shapira http://www.yoavshapira.com
>  
> 
> >-----Original Message-----
> >From: Ma, Liang [mailto:[EMAIL PROTECTED]
> >Sent: Wednesday, November 10, 2004 3:11 PM
> >To: 'Tomcat Users List'
> >Subject: RE: class loader problem?
> >
> >Hi Yoav,
> >
> >Here is the answer to the source code question.
> >
> >Quote starts here:
> >
> >You are using FOP's latest maintenance release (0.20.5), which is FTM
> still
> >recommended for general use.
> >Driver.java, which contains the Driver and Service classes, can be
> found in
> >the Attic at:
> >
> >http://cvs.apache.org/viewcvs.cgi/xml-
> >fop/src/org/apache/fop/apps/Attic/Driv
> >er.java?rev=1.36.2.12&hideattic=0&view=markup
> >
> >
> >The reason why it can't be found at this location:
> >> ==== reply from tomcat-user mailing list ====
> ><snip />
> >>
> http://cvs.apache.org/viewcvs.cgi/xml-fop/src/java/org/apache/
> fop/apps/?
> >
> >is that in the current development version, the Driver class is
> removed.
> >
> >
> >Liang MA
> >Software Analyst
> >--------------------------------------------------
> >RADARSAT Mission Control Centre
> >6767, route de l'Aeroport
> >Saint-Hubert, Quebec
> >J3Y 8Y9 Canada
> >Tel: (450) 926-5099
> >Fax: (450) 926-5127
> >---------------------------------------------------
> >
> >
> >
> >
> >-----Original Message-----
> >From: Shapira, Yoav [mailto:[EMAIL PROTECTED]
> >Sent: November 10, 2004 1:46 PM
> >To: Tomcat Users List
> >Subject: RE: class loader problem?
> >
> >
> >
> >Hi,
> >As the stack trace shows, the exception is in the FOP 
> classes.  So the 
> >amount of blame you can give Tomcat, and the amount of help 
> you can get 
> >on this list, are both severely limited.
> >
> >However, just out of curiosity I went to FOP's CVS repository, to try
> to
> >find the Service or Driver classes that are in the relevant part of
> your
> >stack trace.  I couldn't.  Why aren't they at 
> >http://cvs.apache.org/viewcvs.cgi/xml-fop/src/java/org/apache
> /fop/apps/
> ?
> >If you're using an old version of FOP, the amount of support you can
> get
> >here is even more limited.
> >
> >>root cause
> >>
> >>java.lang.NullPointerException
> >>    at org.apache.fop.apps.Service.providers(Driver.java:597)
> >>    at
> >org.apache.fop.apps.Driver.setupDefaultMappings(Driver.java:319)
> >
> >However, speaking generically without knowing FOP internals well
> (though
> >I've used it in the past): if it works the 2nd time, as you 
> say, that 
> >must mean the Service class has initialized itself properly. 
>  And that 
> >definitely suggests the bug is in FOP itself, if there's a 
> bug at all. 
> >Perhaps some explicit programmatic initialization (e.g. a
> setClassloader
> >call) is needed to make FOP work the first time.
> >
> >Yoav
> >
> >
> >
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> 
> 
> 
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