Java 6: Transformer ignores OutputKeys.STANDALONE?

Question

While testing a very old XML export job for being compatible with Java 6, I noticed a change in the output: the transformer now always adds a standalone="no" to the declaration, no matter what you've told it to do. Though this declaration is merely a hint to the parser, I find it somewhat annoying that even if standalone is set to "yes", the result will be "no" without being reflected in the docs. This happens under Java 6 only, whereas Java 1.4 and Java 5 honour the standalone property you set. Can anyone confirm/explain this?
Here's a test class which produces a very simple XML file named "out.xml" in the cwd:
import java.io.File;
import javax.xml.parsers.*;
import javax.xml.transform.*;
import javax.xml.transform.dom.*;
import javax.xml.transform.stream.*;
import org.w3c.dom.*;
public class XML
  public static void main(String[] args)
    try
      Document doc = DocumentBuilderFactory.newInstance().newDocumentBuilder().newDocument();
      Transformer trans = TransformerFactory.newInstance().newTransformer();
      Element root = doc.createElement("root");
      Element elem = doc.createElement("elem");
      root.appendChild(elem);
      doc.appendChild(root);
      trans.setOutputProperty(OutputKeys.VERSION, "1.0");
      trans.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
      trans.setOutputProperty(OutputKeys.STANDALONE, "yes"); // ignored? wtf
      trans.transform(new DOMSource(doc), new StreamResult(new File("out.xml")));
    catch (Exception ex)
      ex.printStackTrace();
}

Answer 1

Please try doc.setXmlStandalone(true);