XML strictness

[Robert Schuster]

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Hi.
I got a bug report about our DOM parser which I thought to be valid but
then found something that irritates me.

The following program (probably) demonstrates a problem with Classpath'
DOM parser.

package xmlfilter;

!various imports ommitted!

public class XMLFilter {

    public XMLFilter() {
        super();
    }

    public static void main(String[] args) throws Exception {
        /*
         * parses stdin
         */
        Document doc =
DocumentBuilderFactory.newInstance().newDocumentBuilder().parse(System.in);

                  Element newElement = doc.createElement("new");
                  // The next line makes it unhappy ...
                  doc.appendChild(newElement);
        /*
         * serializes xml file to System.out
         */
        TransformerFactory tfactory = TransformerFactory.newInstance();
                Transformer serializer = tfactory.newTransformer();
                doc.normalize();
                serializer.setOutputProperty(OutputKeys.INDENT, "yes");
                serializer.setOutputProperty(OutputKeys.ENCODING, "iso-8859-1");
                serializer.transform(new DOMSource(doc),
                                new StreamResult(System.out));
    }
}

When run as 'echo "<a/>" | jamvm -cp . xmlfilter.XMLFilter' you get the
following exception:

gnu.xml.dom.DomDOMException: The node doesn't belong here.
More Information: document element already present:
gnu.xml.dom.DomElement[a]
Node Name: new
   at gnu.xml.dom.DomDocument.checkNewChild (DomDocument.java:294)
   at gnu.xml.dom.DomDocument.appendChild (DomDocument.java:317)
   at xmlfilter.XMLFilter.main (XMLFilter.java:42)

You get the same message with all proprietary JDKs prior to 1.5 . The
latest incarnation however accepts creating the <new> node and generates
the following XML upon calling 'echo "<a/>" |
/opt/sun-jdk-1.5.0/bin/java xmlfilter.XMLFilter':

<?xml version="1.0" encoding="iso-8859-1"?>
<a/>
<new/>

AFAIK there should/must be only one top-level node which is named <xml>.

I am confused ...
Is Sun breaking the rules here?

cu
Robert
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