JAXB runtime ClassNotFoundException

Question

I'm trying to set up some really basic build stuff using ant and JAXB to handle the transforming of some XML data, but I'm having some trouble getting it to not throw exceptions at runtime. I've successfully got an XJC task running in ant that is definitely outputting all the correct java classes, and they compile without an issue.
The problems occur when I either try to unmarshall or marshall any data using a JAXBContext. basically, my code looks something like this:
public class Deserializer<T>
     private JAXBContext m_context;
     private Unmarshaller m_unmarshaller;
     public Deserializer(String contextPath)
          try
               JAXBContext m_context = JAXBContext.newInstance(contextPath);
               Unmarshaller m_unmarshaller = m_context.createUnmarshaller();
          catch (JAXBException e)
               System.out.println(e);
     public T deserialize(File xml)
          try
               return (T)m_unmarshaller.unmarshal(new FileInputStream(xml));
          catch (FileNotFoundException e)
               System.out.println(e);
          catch (IOException e)
               System.out.println(e);
          catch (JAXBException e)
               System.out.println(e);
          return null;
}and the exception that I am seeing when the unmarshal function is called is this:
[java] Caused by: javax.xml.datatype.DatatypeConfigurationException: Provider org.apache.xerces.jaxp.datatype.DatatypeFactoryImpl not found
     [java]      at javax.xml.datatype.DatatypeFactory.newInstance(DatatypeFactory.java:137)
     [java]      at com.sun.xml.bind.DatatypeConverterImpl.<clinit>(DatatypeConverterImpl.java:740)
     [java]      ... 39 more
     [java] Caused by: java.lang.ClassNotFoundException: org.apache.xerces.jaxp.datatype.DatatypeFactoryImpl
     [java]      at org.apache.tools.ant.AntClassLoader.findClassInComponents(AntClassLoader.java:1400)
     [java]      at org.apache.tools.ant.AntClassLoader.findClass(AntClassLoader.java:1341)
     [java]      at org.apache.tools.ant.AntClassLoader.loadClass(AntClassLoader.java:1094)
     [java]      at java.lang.ClassLoader.loadClass(ClassLoader.java:250)
     [java]      at javax.xml.datatype.FactoryFinder.getProviderClass(FactoryFinder.java:115)
     [java]      at javax.xml.datatype.FactoryFinder.newInstance(FactoryFinder.java:146)
     [java]      at javax.xml.datatype.FactoryFinder.findJarServiceProvider(FactoryFinder.java:298)
     [java]      at javax.xml.datatype.FactoryFinder.find(FactoryFinder.java:223)
     [java]      at javax.xml.datatype.DatatypeFactory.newInstance(DatatypeFactory.java:131)
     [java]      ... 40 morewhich looks like maybe my classpath might be wrong? im really not sure. Ive tried downloading xerces .jar's and pointing the classpath at that, with identical results. For reference, I'm not using any IDE's, just good old vim on a fresh mac running snow leopard.
Any help at all would be greatly appreciated.
Thanks,
s.

Answer 1

This is the ant code im using:
     <java classname="testjaxb.testjaxbCLI">
            <classpath>
               <pathelement path="${basedir}/tools/testjaxb/build" />
               <fileset dir="${lib.dir}/commons-cli-1.2"/>
               <fileset dir="${lib.dir}/jaxb"/>
            </classpath>
     </java>The buid directory is where all class files from the compilation stage (both my stuff and the stuff generated by xjc) are dumped. The commons-cli-1.2 directory is for apache commandline parsing classes. the jaxb directory contains these jars (just in case i'm missing one for some reason):
activation.jar
jaxb-impl.jar
jaxb-xjc.jar     
jaxb1-impl.jar
jaxb-api.jar
jsr173_1.0_api.jar
s