FULL PRODUCT VERSION :
java version "1.6.0_01"
Java(TM) SE Runtime Environment (build 1.6.0_01-b06)
Java HotSpot(TM) Client VM (build 1.6.0_01-b06, mixed mode, sharing)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [Version 5.1.2600]

A DESCRIPTION OF THE PROBLEM :
Transforms where the StreamResult is created with a file specified by a UNC path fail with a FileNotFoundException. The pathnreported by that exception is not the same as the path supplied to the StreamResult constructor. For example, \\sonata\test\test.xml becomes \test\test.xml

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Run the attached code supplying a UNC path as the sole argument.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
A trivial xml file should be written to the specified file.
ACTUAL -
Writing to \\sonata\test\test.xml
Exception in thread "main" javax.xml.transform.TransformerException: java.io.FileNotFoundException: \test\test.xml (The system cannot find the path specified)


ERROR MESSAGES/STACK TRACES THAT OCCUR :
Exception in thread "main" javax.xml.transform.TransformerException: java.io.FileNotFoundException: \test\test.xml (The system cannot find the path specified)
	at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.getOutputHandler(TransformerImpl.java:491)
	at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform(TransformerImpl.java:298)
	at jaxp.StreamResultUNC.main(StreamResultUNC.java:37)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at com.intellij.rt.execution.application.AppMain.main(AppMain.java:90)
Caused by: java.io.FileNotFoundException: \test\test.xml (The system cannot find the path specified)
	at java.io.FileOutputStream.open(Native Method)
	at java.io.FileOutputStream.<init>(FileOutputStream.java:179)
	at java.io.FileOutputStream.<init>(FileOutputStream.java:70)
	at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.getOutputHandler(TransformerImpl.java:463)
	... 7 more
---------
java.io.FileNotFoundException: \test\test.xml (The system cannot find the path specified)
	at java.io.FileOutputStream.open(Native Method)
	at java.io.FileOutputStream.<init>(FileOutputStream.java:179)
	at java.io.FileOutputStream.<init>(FileOutputStream.java:70)
	at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.getOutputHandler(TransformerImpl.java:463)
	at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform(TransformerImpl.java:298)
	at jaxp.StreamResultUNC.main(StreamResultUNC.java:37)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at com.intellij.rt.execution.application.AppMain.main(AppMain.java:90)


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
import org.w3c.dom.Document;
import org.w3c.dom.Element;

import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import java.io.File;

/** Test Windows UNC paths.
 * Universal Naming Convention paths fail.
 * Created by IntelliJ IDEA.
 * User: mthornton
 * Date: 25-Apr-2007
 * Time: 21:36:44
 * To change this template use File | Settings | File Templates.
 */
public class StreamResultUNC
{
	public static void main(String[] args) throws Exception {
		// create a document to write
		DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
		DocumentBuilder builder = factory.newDocumentBuilder();
		Document doc = builder.newDocument();
		Element root = doc.createElement("test");
		doc.appendChild(root);
		// create an identity transform
		Transformer t = TransformerFactory.newInstance().newTransformer();
		File f = new File(args[0]);
		StreamResult result = new StreamResult(f);
		DOMSource source = new DOMSource(doc);
		System.out.println("Writing to "+f);
		t.transform(source, result);
	}
}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
Map the share to a drive and use the drive based path instead.
Alternatively open the file first and use the OutputStream version of the StreamResult constructor.