I see the following NPE with stax FCS(checked in JAXWS workspace). The program reads events from XMLEventReader and writes into XMLEventWriter. Attaching the program and the xml file. This is reported by one of the JAX-WS java.net users.

bash-3.00$ java Main
Exception in thread "main" java.lang.NullPointerException
        at com.sun.xml.stream.writers.UTF8OutputStreamWriter.write(UTF8OutputStreamWriter.java:128)
        at com.sun.xml.stream.writers.XMLStreamWriterImpl.writeDefaultNamespace(XMLStreamWriterImpl.java:728)
        at com.sun.xml.stream.writers.XMLStreamWriterImpl.writeNamespace(XMLStreamWriterImpl.java:914)
        at com.sun.xml.stream.writers.XMLEventWriterImpl.add(XMLEventWriterImpl.java:112)
        at Main.main(Main.java:27)