Why does this code keep triggering the SaxParseException : ""PI must not start with xml"?

Question

This code is used to generate a XML document from its String representation. It works fine in my small unit tests, but fails in my actual xml data. The line where it triggers is Document doc = db.parse(is);

Any ideas?

public static Document FromString(String xml)
{
    // from http://www.rgagnon.com/javadetails/java-0573.html
    try
    {
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
        DocumentBuilder db = dbf.newDocumentBuilder();
        InputSource is = new InputSource();
        is.setCharacterStream(new StringReader(xml));

        Document doc = db.parse(is);
        doc.normalize();

        return doc;
    }
    catch (Exception e)
    {
        Log.WriteError("Failed to parse XML", e, "XML.FromString(String)");
        return null;
    }
}

Answer 1

Thanks for your help everyone.

I discarded the <?xml version="1.0" encoding="utf-8"?> which cleared this error. Still don't understand what the reason for this might be, but it worked nonetheless.

I went on to find one of my buffered writers (when extracting from a zip file into memory) wasn't being flushed, which was causing the xml string to be incomplete.

Thanks everyone for your help!