I'm guessing you're reusing the Transformer object in multiple threads at the same time. The Transformer object is not thread-safe. You'll need to share the Templates object instead, and generate the Transformer object in each thread.
> -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] > > We use Xalan in a framework that transforms and audits > e-business catalogs since 2001. This framework builds one > transformer and reuses up to more > than 100000 times. And it works fine. > > The transformations are performed (essentially) in the > following code fragment: > > JDOMResult out = new JDOMResult (); > transformer.transform (new JDOMSource (in), out); > > After the update from JDOM beta 0.9 to JDOM 1.0 (and > with a different XSLT-Script for a different, customized data > model) the transform method > throws sometimes a NullpointerException without any > Stacktrace or message in e.getMessage(). > > One catalog under test has about 33000 Positions, each > position is transformed by one call of the method > transformer.transform(...). > With the identical catalog the Exception is sometimes > thrown during one export of the catalog, sometimes not. > > The NullpointerException not has been thrown two times > at the same position in the different exports. So it is > difficult to correlate the Exception to the use > of a specific template or line of code in the > XSLT-Script. The Script has about 1200 lines of code and uses > Java extension functions. > > This NullpointerException has be reproduced with the JDK 1.4.2 > > * under Fedora Core 3 with and without the NPTL and > XALAN 2.5.1, > * and with Fedora Core 3 without NPTL and XALAN 2.7.0, > * and has been reproduced with XALAN 2.5.1 under > Fedora Core 2 without NPTL. > > We have not been able to reproduce this under Windows 2000. > > As a work around I build a new transformation engine > on each transformation, but this slows down the whole > application by a factor of 3. > This work around has been tested with more the 40 > exports of the specific catalog and the Exception has not > been thrown. When the > transformer is reused then the Exception occurs in > abouts 50 % of the exports. > > I wish to thank you for the time you spend in reading > this email. > > Any help is welcome! > > Greetings > > Andreas > > > -------------------------------------------------------------- > ------------- > > Andreas Rulle > > Intermoves AG > Technologiepark 19 > 33100 Paderborn > > >
