code: @Override
    public void addXMLDecl(String versionInfo,
                           String encoding,
                           boolean standalone)
    {
      _xml.append("<?xml version=\"").append(versionInfo);
      _xml.append("\" encoding=\"");
      _xml.append(encoding).append("\" standalone=\"");
      _xml.append(standalone ? "yes" : "no");
      _xml.append("\"?>\n");
    }
docs: Adds the XML declaration (<code>&lt;?xml version="1.0" encoding="UTF-8"
  standalone="yes"?&gt;</code>)
  
  @param versionInfo the version info
  @param encoding the encoding (eg: UTF-8)
  @param standalone <code>true</code> for standalone