STaX code is not working with JAXB

Question

Found a sample STaX code in below link: http://www.javarants.com/2006/04/30/simple-and-efficient-xml-parsing-using-jaxb-2-0/comment-page-1/

The below code doesn't work. I am not what is missing.

JAXBContext ctx = JAXBContext.newInstance("com.sampullara.findbugs.om");
        Unmarshaller um = ctx.createUnmarshaller();
        int bugs = 0;
        while (xmlfer.peek() != null) {
             Object o = um.unmarshal(xmler);
             if (o instanceof BugInstance) {
                 BugInstance bi = (BugInstance) o;
                 // process the bug instance
                 bugs++;
             }
    }

What is missing in the above code?