Local part cannot be "null" when creating a QName

Question

We are trying to track down a bug. We get the above error in the logs.

Can anyone explain what this message means? Are there any typical reasons for getting this message?

The stacktrace is:

org.apache.axiom.om.OMException: java.lang.IllegalArgumentException: local part cannot be "null" when creating a QName
            at org.apache.axiom.om.impl.builder.StAXOMBuilder.next(StAXOMBuilder.java:206)
            at org.apache.axiom.om.impl.llom.OMNodeImpl.build(OMNodeImpl.java:318)
            at org.apache.axiom.om.impl.llom.OMElementImpl.build(OMElementImpl.java:618)
            at org.apache.axis2.jaxws.message.util.impl.SAAJConverterImpl.toOM(SAAJConverterImpl.java:147)
            at org.apache.axis2.jaxws.message.impl.XMLPartImpl._convertSE2OM(XMLPartImpl.java:77)
            at org.apache.axis2.jaxws.message.impl.XMLPartBase.getContentAsOMElement(XMLPartBase.java:203)
            at org.apache.axis2.jaxws.message.impl.XMLPartBase.getAsOMElement(XMLPartBase.java:255)
            at org.apache.axis2.jaxws.message.impl.MessageImpl.getAsOMElement(MessageImpl.java:464)
            at org.apache.axis2.jaxws.message.util.MessageUtils.putMessageOnMessageContext(MessageUtils.java:202)
            at org.apache.axis2.jaxws.core.controller.AxisInvocationController.prepareRequest(AxisInvocationController.java:370)
            at org.apache.axis2.jaxws.core.controller.InvocationController.invoke(InvocationController.java:120)
            at org.apache.axis2.jaxws.client.proxy.JAXWSProxyHandler.invokeSEIMethod(JAXWSProxyHandler.java:317)
            at org.apache.axis2.jaxws.client.proxy.JAXWSProxyHandler.invoke(JAXWSProxyHandler.java:148)

Answer 1

I got the same error message (local part cannot be "null" when creating a QName) while trying to construct a org.w3c.dom.Document from String. The problem went away after calling setNamespaceAware(true) on DocumentBuilderFactory. Working code snippet is given below.

private static Document getDocumentFromString(final String xmlContent)
  throws Exception
{
    DocumentBuilderFactory documentBuilderFactory =
                                DocumentBuilderFactory.newInstance();
    documentBuilderFactory.setNamespaceAware(true);
    try
    {
        return documentBuilderFactory
                    .newDocumentBuilder()
                    .parse(new InputSource(new StringReader(xmlContent)));
    }
    catch (Exception e)
    {
        throw new RuntimeException(e);
    }
}   

Answer 2

It means you are creating a DOM element or attribute using one of the namespace methods like createElementNS thus

document.createElementNS(namespace, null)

or createElementNS or setAttrbuteNS and the second argument, the qname is null, or includes a prefix but no local part as in "foo:".

EDIT:

I would try to run the XML it's parsing through a validator. It's likely there's some tag or attribute name like foo: or foo:bar:baz that is a valid XML identifier but invalid according to the additional restrictions introduced by XML namespaces.