I'm deploying an application (maven built) that produces both XML and JSON data using the jersey-json module. Deploying the application on WebLogic with the <prefer-web-inf-classes> flag set causes a LinkageError due to multiple instances of the javax.xml.namespace.QName class being found. Looking inside the war file I can see a "stax 1.0.1" module that carries its own instance of QName, and is included transitively by jersey-json via a dependency on the jettison module. The same jersey-json module depends on the "stax 1.0-2" package (via the jaxb-impl dependency) that causes no issues. Shouldn't jersey depend just on the "stax 1.0-2" module, since QName has been part of the standard library for ages?