Org.xml.sax.SAXParseException: Document root element is missing.

Question

Hi,
I am trying to get the portal login id from a weblogic server based application from iplaet portal server.
I get this follwoing error
org.xml.sax.SAXParseException: Document root element is missing.
at com.sun.xml.parser.Parser.fatal(Parser.java:2817)
at com.sun.xml.parser.Parser.fatal(Parser.java:2805)
at com.sun.xml.parser.Parser.parseInternal(Parser.java:493)
at com.sun.xml.parser.Parser.parse(Parser.java:284)
at com.sun.xml.tree.XmlDocument.createXmlDocument(XmlDocument.java:226)
at com.iplanet.portalserver.util.XMLParser.<init>(XMLParser.java:70)
at com.iplanet.portalserver.naming.share.NamingResponseParser.<init>(NamingResponseParser.java:33)
at com.iplanet.portalserver.naming.share.NamingResponse.parseXML(NamingResponse.java:74)
at com.iplanet.portalserver.naming.WebtopNaming.updateNamingTable(WebtopNaming.java:174)
at com.iplanet.portalserver.naming.WebtopNaming.getNamingProfile(WebtopNaming.java:155)
at com.iplanet.portalserver.naming.WebtopNaming.getServiceURL(WebtopNaming.java:57)
at com.iplanet.portalserver.session.Session.getSessionServiceURL(Session.java:534)
at com.iplanet.portalserver.session.Session.getSessionServiceURL(Session.java:520)
at com.iplanet.portalserver.session.Session.getSession(Session.java:414)
at jsp_servlet.__eatonPortalLogin._jspService(__eatonPortalLogin.java:155)
at weblogic.servlet.jsp.JspBase.service(JspBase.java:27)
at weblogic.servlet.internal.ServletStubImpl$ServletInvocationAction.run(ServletStubImpl.java:1075)
at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:418)
at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:462)
at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:306)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:5517)
at weblogic.security.service.SecurityServiceManager.runAs(SecurityServiceManager.java:685)
at weblogic.servlet.internal.WebAppServletContext.invokeServlet(WebAppServletContext.java:3156)
at weblogic.servlet.internal.ServletRequestImpl.execute(ServletRequestImpl.java:2506)
at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:234)
at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:210)
<May 19, 2004 9:01:12 AM EDT> <Error> <HTTP> <101017> <[ServletContext(id=4873279,name=ematrix,context-path=/ematrix)] Root cause of ServletException
com.iplanet.portalserver.session.SessionException
at com.iplanet.portalserver.session.Session.getSessionServiceURL(Session.java:539)
at com.iplanet.portalserver.session.Session.getSessionServiceURL(Session.java:520)
at com.iplanet.portalserver.session.Session.getSession(Session.java:414)
at jsp_servlet.__eatonPortalLogin._jspService(__eatonPortalLogin.java:155)
at weblogic.servlet.jsp.JspBase.service(JspBase.java:27)
at weblogic.servlet.internal.ServletStubImpl$ServletInvocationAction.run(ServletStubImpl.java:1075)
at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:418)
at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:462)
at weblogic.servlet.internal.ServletStubImpl.invokeServlet(ServletStubImpl.java:306)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:5517)
at weblogic.security.service.SecurityServiceManager.runAs(SecurityServiceManager.java:685)
at weblogic.servlet.internal.WebAppServletContext.invokeServlet(WebAppServletContext.java:3156)
at weblogic.servlet.internal.ServletRequestImpl.execute(ServletRequestImpl.java:2506)
at weblogic.kernel.ExecuteThread.execute(ExecuteThread.java:234)
at weblogic.kernel.ExecuteThread.run(ExecuteThread.java:210)
Any help/pointers will be appreciated.
Ashish

Answer 1

Just for anyone else who hits this problem: I encountered the same issue with an XML document that XMLSpy claims is quite well formed. I opened the document in a hex editor, and there at the from was a three-byte byte order marker - the marker that I believe the UTF-8 standard says is optional. I removed these three bytes, and the file was parsed correctly.
In this case, the XML file was created using a Microsft DOM (save).
My solution is to make the java parser - as I use it - a tad more robust: Open the file and create an input stream - a pushback input stream. Read the first three bytes; if they are NOT a BOM, then push those bytes back. Now - in any case - give the stream to the parser to read.
try {
// Open file for reading.
f = new File(path);
FileInputStream fis = new FileInputStream(f);
PushbackInputStream pis = new PushbackInputStream(fis);
byte[] buf = new byte[3];
pis.read(buf, 0, 3);
if (! (buf[0] == 0x00EF) && (buf[1] == 0x00BB) && (buf[2] == 0x00BF) ) {
     pis.unread(buf, 0, 3);
builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
doc = builder.parse(pis);
catch (Exception x) {
     x.printStackTrace();
}