I get a NoClassDefFoundError for the org/jdom/Document class when I try to execute an XPath expression on a web application deployed to Oracle Application Server 9052 (yeah I know, it’s a pos).  It makes absolutely no sense because I’ve had no problems with JDOM for parsing and walking the document tree in the same application.  This exception only occurs when I try to execute an XPath expression to get a specific element in the document.  The same war application works correctly in Tomcat 5.

This is the function where the exception is thrown:

    private Element findItemElement(Document d, String id) {

        String expr = "/ItemReviewData/ContentDictionary/Items/Item[@id='" + id + "']";

        try {

            XPath xpath = XPath.newInstance(expr);

            return (Element) xpath.selectSingleNode(d);

        } catch (JDOMException e) {

            e.printStackTrace();

        } catch (Exception e) {

            e.printStackTrace();

        }

        return null;

    }

This is the stack trace:

500 Internal Server Error

java.lang.NoClassDefFoundError: org/jdom/Document       at org.jaxen.jdom.DocumentNavigator.getDocumentNode(DocumentNavigator.java:313)           at org.jaxen.expr.DefaultAbsoluteLocationPath.evaluate(DefaultAbsoluteLocationPath.java:113)            at org.jaxen.expr.DefaultXPathExpr.asList(DefaultXPathExpr.java:107)            at org.jaxen.BaseXPath.selectNodesForContext(BaseXPath.java:716)            at org.jaxen.BaseXPath.selectNodes(BaseXPath.java:239)    at org.jaxen.BaseXPath.selectSingleNode(BaseXPath.java:262)     at org.jdom.xpath.JaxenXPath.selectSingleNode(JaxenXPath.java:153)           at org.nbme.fbp.ir.service.impl.XmlBluePrintServiceImpl.findItemElement(XmlBluePrintServiceImpl.java:233)       at org.nbme.fbp.ir.service.impl.XmlBluePrintServiceImpl.updateItemReviewStatus(XmlBluePrintServiceImpl.java:170)      at org.nbme.fbp.ir.action.itemreview.ItemPageAction.executeAction(ItemPageAction.java:35)   at org.nbme.fbp.ir.action.SpringBaseAction.execute(SpringBaseAction.java:39)          at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:419)       at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:224)   at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)     at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)          at javax.servlet.http.HttpServlet.service(HttpServlet.java:740)  at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)          at com.evermind[Oracle Application Server Containers for J2EE 10g (9.0.4.1.0)].server.http.ResourceFilterChain.doFilter(ResourceFilterChain.java:65)    at clime.messadmin.core.MessAdminFilter.doFilter(MessAdminFilter.java:166)           at com.evermind[Oracle Application Server Containers for J2EE 10g (9.0.4.1.0)].server.http.EvermindFilterChain.doFilter(EvermindFilterChain.java:16)     at org.nbme.common.security.SecurityFilter.doFilter(SecurityFilter.java:70)    at com.evermind[Oracle Application Server Containers for J2EE 10g (9.0.4.1.0)].server.http.EvermindFilterChain.doFilter(EvermindFilterChain.java:20)          at com.opensymphony.module.sitemesh.filter.PageFilter.doFilter(PageFilter.java:39)   at com.evermind[Oracle Application Server Containers for J2EE 10g (9.0.4.1.0)].server.http.ServletRequestDispatcher.invoke(ServletRequestDispatcher.java:600)            at com.evermind[Oracle Application Server Containers for J2EE 10g (9.0.4.1.0)].server.http.ServletRequestDispatcher.forwardInternal(ServletRequestDispatcher.java:317)            at com.evermind[Oracle Application Server Containers for J2EE 10g (9.0.4.1.0)].server.http.HttpRequestHandler.processRequest(HttpRequestHandler.java:793)  at com.evermind[Oracle Application Server Containers for J2EE 10g (9.0.4.1.0)].server.http.AJPRequestHandler.run(AJPRequestHandler.java:208)           at com.evermind[Oracle Application Server Containers for J2EE 10g (9.0.4.1.0)].server.http.AJPRequestHandler.run(AJPRequestHandler.java:125)         at com.evermind[Oracle Application Server Containers for J2EE 10g (9.0.4.1.0)].util.ReleasableResourcePooledExecutor$MyWorker.run(ReleasableResourcePooledExecutor.java:192)    at java.lang.Thread.run(Thread.java:534)

If anybody has any ideas, I’ll be eternally grateful.  I’m pretty sure it has to do with Oracle but I would love to find a workaround.