JAXB Unmarshaller/Marshaller operation differences.

Question

I am using jaxb-ra-2.1.8 and am trying to write a simple program to read xml marshall it to a file then immediately read it back in using the following:
import java.io.File;
import java.io.IOException;
import javax.xml.XMLConstants;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Marshaller;
import javax.xml.bind.Unmarshaller;
import javax.xml.bind.ValidationEvent;
import javax.xml.bind.ValidationEventHandler;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.transform.stream.StreamSource;
import javax.xml.validation.Schema;
import javax.xml.validation.SchemaFactory;
import org.xml.sax.SAXException;
import com.namespace.test.base.Root;
import com.namespace.test.extension.Extension;
public class XmlJaxStuffWeb implements ValidationEventHandler{
     public static void main(String[] args) throws JAXBException, ParserConfigurationException, SAXException, IOException{
          JAXBContext jaxbContext = JAXBContext.newInstance("com.namespace.test.abstracttype:com.namespace.test.base");
          StreamSource[] streams = new StreamSource[3];
          streams[0] = new StreamSource(new File("C:/development/libraries/jaxb-ri-2.1.8/bin/abstract/Extension.xsd"));
          streams[1] = new StreamSource(new File("C:/development/libraries/jaxb-ri-2.1.8/bin/abstract/Base.xsd"));
          streams[2] = new StreamSource(new File("C:/development/libraries/jaxb-ri-2.1.8/bin/abstract/AbstractType.xsd"));
          Schema s = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI).newSchema(streams);
          //javax.xml.validation.Validator v = s.newValidator();
          writeXml(jaxbContext, s);
          readXml(jaxbContext, s);
          //System.out.println
          //System.out.println(jaxbContext.toString());
          //jaxbContext.createValidator();
     public static void readXml(JAXBContext jaxbContext, Schema s) throws JAXBException, SAXException, IOException{
          Unmarshaller un = jaxbContext.createUnmarshaller();
          un.setSchema(s);
          un.setEventHandler(new XmlJaxStuffWeb());
          //un.setValidating(true);
          Object obj = un.unmarshal(new File("c:/test.xml"));
          System.out.println(obj.getClass());
     public static void writeXml(JAXBContext jaxbContext, Schema s) throws JAXBException, SAXException, IOException{
          Root r = new Root();
          r.setHolder("Holder");
          Extension e = new Extension();
          e.setExtendedString("BLAH");
          e.setText("blah");
          com.namespace.test.extension.ObjectFactory f = new com.namespace.test.extension.ObjectFactory();
          r.setAbstractElement(f.createExtension(e));
          //StringWriter b = new StringWriter();
          Marshaller marshaller = jaxbContext.createMarshaller();
          marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
          marshaller.setSchema(s);
          marshaller.setEventHandler(new XmlJaxStuff());
          marshaller.marshal( r, new File("c:/test.xml") );
          //System.out.println(b);
     /* (non-Javadoc)
      * @see javax.xml.bind.ValidationEventHandler#handleEvent(javax.xml.bind.ValidationEvent)
     public boolean handleEvent(ValidationEvent arg0) {
          System.out.println(arg0.getMessage());
          //ValidationEventLocator l = arg0.getLocator();
          return false;
}The write is performed without issue, but the read bombs saying an expected element is missing, which makes no sense since I do validation before marshalling and unmarshalling. It looks like the Unmarshaller is searching the JAXBContext (i.e. not reading the @XmlSeeAlso annotation) differently than the Marshaller because if I put the other package in the JAXBContext it works fine for both reads and writes. Is this expected or is there a bug that exists that causes this behavior?
It may also be worth noting that I do not get an error if I don't specify a custom eventhandler.
Edited by: JaM2003 on Oct 14, 2008 2:00 PM

Answer 1

Hi Jason,
Below is the sample.....You can use this..
JAXBElement<Task> root = null;
          try {
               ByteArrayInputStream input = new ByteArrayInputStream(
                         xmlStr.getBytes());
               JAXBContext jc = JAXBContext.newInstance(Task.class);
               Unmarshaller u = jc.createUnmarshaller();
               StreamSource sc = new StreamSource(new StringReader(
                         xmlStr.toString()));
               root = u.unmarshal(new StreamSource(input), Task.class);
          } catch (Exception e) {
               e.printStackTrace();
          }