XML and XPath in WebSphere 6.0.2.7

Question

We are running websphere 6.0.2.7 to host an application called xPression (print app). xPression allows for user exits (a plugin) to be written as a java class and used in the report processing. We have written several of these to great affect but until now they've used basic java functionality.
I want to load an xml document and the query it with xpath to retrieve specific data for use in the reports. I have looked at several methods and the initial thought was to use JDOM as there was no built in support for xpath with Java 1.4.2. This wouldn't work on the server as there was a xerces conflict and I couldn't fix it by changing class paths without potentially breaking xpression.
I then found in the ibm JRE on the websphere server a xml.jar file which contained various classes and can deal with xPath. I have written a user exit to use the classes in this jar and it works on my local machine (I have copied the JRE to my machine and added it as a platform in NetBeans to use in my user exit project).
If I run the user exit class on the server I run into problems with class casting exceptions but I cannot work out why. The code causing the problem is the call to the parser to build the xml dom:
//just to show what classes I'm using
import org.w3c.dom.Document;
import org.apache.xerces.dom.DeferredElementImpl;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.transform.TransformerException;
//class decs etc
        //load document method...
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        DocumentBuilder db = dbf.newDocumentBuilder();
        Document doc = db.parse();         //this is where the exception is caused
        doc.normalize();If this is executed, in websphere under xpression, then I get the following stack trace:
UEID :     1520020249
ErrorCode :     5162
ErrorMessage :     There is an exception during the execution of user exist method,nfumutual.xpression.userexits.UEInsertableText.UE_GetInsertableText().
StackTrace :     java.lang.reflect.InvocationTargetException
...some corba stuff from xpression
Caused by: java.lang.ClassCastException: org.apache.xerces.jaxp.DocumentBuilderFactoryImpl
     at javax.xml.parsers.DocumentBuilderFactory.newInstance(Unknown Source)
     at nfumutual.xpression.userexits.UEInsertableText.loadDocument(UEInsertableText.java:66)
     at nfumutual.xpression.userexits.UEInsertableText.UE_GetInsertableText(UEInsertableText.java:55)
     ... 22 more
So... I thought instead of calling DocumentBuilderFactory.newInstance() to get an instance of a DocumentBuilderFactory, I'd explicitly create a DocumentBuilderFactoryImpl object:
        DocumentBuilderFactory dbf = new org.apache.xerces.jaxp.DocumentBuilderFactoryImpl();      
        DocumentBuilder db = dbf.newDocumentBuilder();      
        Document doc = db.parse();
        doc.normalize();This again worked on my local machine using the same JRE as websphere, but would not run under websphere:
UEID :     551408526
ErrorCode :     5162
ErrorMessage :     There is an exception during the execution of user exist method,nfumutual.xpression.userexits.UEInsertableText.UE_GetInsertableText().
StackTrace :     java.lang.reflect.InvocationTargetException
...corba/xpression stuff
     at com.ibm.ws.util.ThreadPool$Worker.run(ThreadPool.java:1469)
Caused by: java.lang.ClassCastException: org.apache.xerces.parsers.StandardParserConfiguration
     at org.apache.xerces.parsers.DOMParser.<init>(Unknown Source)
     at org.apache.xerces.parsers.DOMParser.<init>(Unknown Source)
     at org.apache.xerces.jaxp.DocumentBuilderImpl.<init>(Unknown Source)
     at org.apache.xerces.jaxp.DocumentBuilderFactoryImpl.newDocumentBuilder(Unknown Source)
     at nfumutual.xpression.userexits.UEInsertableText.loadDocument(UEInsertableText.java:68)
     at nfumutual.xpression.userexits.UEInsertableText.UE_GetInsertableText(UEInsertableText.java:55)
     ... 22 more
This time I get a StandardParserConfiguration causing class cast exception.
I thought I maybe running into the same problems as I had with JDOM - conflicting versions of classes - but I have written some code to return where a class is being loaded from, and everything I am using is coming from the xml.jar in the JRE - the same as what I am compiling and running against on my local machine.
Can anyone offer any advice as to how I can get this to work?

Answer 1

There is a forum that deals with xml questions where this is more likely to get an answer.