NUll pointer exception in XML sig program

Hi all,

i have written a progam for xml siganature which is as follows.
i am using smart card for this.null pointer excepton is in red colored line.

please help me.
thanks.

program and out put is as follows.

/*
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* and open the template in the editor.
*/

package sig;

/**
*
* @author cabin6
*/
import java.io.FileNotFoundException;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.xml.crypto.dsig.*;
import javax.xml.crypto.dsig.keyinfo.*;
import javax.xml.crypto.dsig.spec.*;
import javax.xml.crypto.dsig.dom.*;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.OutputStream;
import org.w3c.dom.Document;
import java.security.cert.*;
import java.security.*;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerFactory;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.stream.StreamResult;
import java.util.Enumeration;
import com.sun.org.apache.xml.internal.security.Init.*;
import java.io.InputStream;
import java.util.Arrays;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.transform.Result;
import javax.xml.transform.Source;
import org.w3c.dom.Node;

/**
*
* @author cabin6
*/

public class Main
{
public static void main(String a[])throws Exception{
try{

// Create a DOM XMLSignatureFactory that will be used to
// generate the enveloped signature.

String providerName = System.getProperty("jsr105Provider","org.jcp.xml.dsig.internal.dom.XMLDSigRI");
XMLSignatureFactory fac = XMLSignatureFactory.getInstance("DOM",(Provider) Class.forName(providerName).newInstance());

// Create a Reference to the enveloped document (in this case,
// you are signing the whole document, so a URI of "" signifies
// that, and also specify the SHA1 digest algorithm and
// the ENVELOPED Transform.

String inputFilename = "c:/result.xml";
InputStream inputStream = new FileInputStream(inputFilename);
DocumentBuilderFactory documentBuilderFactory =DocumentBuilderFactory.newInstance();
documentBuilderFactory.setNamespaceAware(true);
DocumentBuilder builder = documentBuilderFactory.newDocumentBuilder();
Document document = builder.parse(inputStream);
Node node = document.getDocumentElement();

// STEP 4: Prepare the XMLSignatureFactory
// Create DigestMethod
String digestAlgorithm = DigestMethod.SHA1;
DigestMethodParameterSpec digestParams = null;
DigestMethod digestMethod = fac.newDigestMethod(digestAlgorithm, digestParams);

// Create Transform
String transformAlgorithm = Transform.ENVELOPED;
TransformParameterSpec transformParams = null;
Transform transform = fac.newTransform(transformAlgorithm, transformParams);

// Create Reference
String uri = "";
List transforms = Arrays.asList(transform);
String type = null;
String id = null;
Reference reference = fac.newReference(uri, digestMethod,transforms, type, id);

// Create CanonicalizationMethod
String canonAlgorithm = CanonicalizationMethod.INCLUSIVE_WITH_COMMENTS;
C14NMethodParameterSpec canonParams = null;
CanonicalizationMethod canonicalizationMethod =fac.newCanonicalizationMethod(canonAlgorithm, canonParams);

// Create SignatureMethod
String signatureAlgorithm = SignatureMethod.RSA_SHA1;
SignatureMethodParameterSpec signatureParams = null;
SignatureMethod signatureMethod =fac.newSignatureMethod(signatureAlgorithm, signatureParams);

// Create SignedInfo
List references = Arrays.asList(reference);
SignedInfo si = fac.newSignedInfo(canonicalizationMethod,signatureMethod, references);

// Load the KeyStore and get the signing key and certificate.
String configName = "C:/Program Files/Java/jdk1.6.0_05/jre/lib/ext/pkcs11.cfg";
Provider p = new sun.security.pkcs11.SunPKCS11(configName);
Security.addProvider(p);
p.list(System.out);

String password = "PASSWORD";
char[] pin = password.toCharArray();
KeyStore ks = KeyStore.getInstance("PKCS11");
ks.load(null, pin);

Enumeration aliasesEnum = ks.aliases();
String alias = (String) aliasesEnum.nextElement();
System.out.println("Alias: " + alias);
PrivateKey privateKey = (PrivateKey) ks.getKey(alias, null);
System.out.println("Private key: " + privateKey);
X509Certificate cert = (X509Certificate) ks.getCertificate(alias);
System.out.println("Certificate: " + cert);

// Create the KeyInfo containing the X509Data.
KeyInfoFactory kif = fac.getKeyInfoFactory();
List x509Content = new ArrayList();
x509Content.add(cert.getSubjectX500Principal().getName());
x509Content.add(cert);
X509Data xd = kif.newX509Data(x509Content);
KeyInfo ki = kif.newKeyInfo(Collections.singletonList(xd));
System.out.println("csl:"+Collections.singletonList(xd));

DOMSignContext signContext = new DOMSignContext(privateKey, node);
// Create the XMLSignature, but don't sign it yet.
XMLSignature signature = fac.newXMLSignature(si,ki);

// Marshal, generate, and sign the enveloped signature.
signature.sign(signContext);

String outputFilename = "C:/Documents and Settings/cabin6.NIC/Desktop/signedPurchaseOrder.xml";
OutputStream outputStream = new FileOutputStream(outputFilename);
Source xmlSource = new DOMSource(document);
Result outputTarget = new StreamResult(outputStream);
TransformerFactory transformerFactory =TransformerFactory.newInstance();
Transformer transformer =transformerFactory.newTransformer();
transformer.transform(xmlSource, outputTarget);

}
catch (FileNotFoundException ex)
{
Logger.getLogger(Main.class.getName()).log(Level.SEVERE, null, ex);
}
}
}

out put is :

run:
-- listing properties --
Alg.Alias.MessageDigest.SHA=SHA1
KeyPairGenerator.DH=sun.security.pkcs11.P11KeyPairGenerator
KeyGenerator.DESede=sun.security.pkcs11.P11KeyGenerator
Alg.Alias.KeyAgreement.DiffieHellman=DH
Alg.Alias.KeyPairGenerator.DiffieHellman=DH
Provider.id name=SunPKCS11-SunPKCS11-rainbow_token
KeyGenerator.ARCFOUR=sun.security.pkcs11.P11KeyGenerator
Signature.SHA512withRSA=sun.security.pkcs11.P11Signature
Signature.MD2withRSA=sun.security.pkcs11.P11Signature
Alg.Alias.Cipher.RC4=ARCFOUR
KeyFactory.DH=sun.security.pkcs11.P11DHKeyFactory
Cipher.DESede/CBC/NoPadding=sun.security.pkcs11.P11Cipher
Provider.id version=1.6
KeyFactory.RSA=sun.security.pkcs11.P11RSAKeyFactory
SecretKeyFactory.ARCFOUR=sun.security.pkcs11.P11SecretKeyFactory
Alg.Alias.Signature.NONEwithDSA=RawDSA
Signature.MD5withRSA=sun.security.pkcs11.P11Signature
Cipher.DES/CBC/NoPadding=sun.security.pkcs11.P11Cipher
MessageDigest.SHA1=sun.security.pkcs11.P11Digest
SecretKeyFactory.DESede=sun.security.pkcs11.P11SecretKeyFactory
Alg.Alias.KeyGenerator.RC4=ARCFOUR
KeyGenerator.DES=sun.security.pkcs11.P11KeyGenerator
Alg.Alias.KeyStore.PKCS11-SunPKCS11-rainbow_token=PKCS11
Cipher.ARCFOUR=sun.security.pkcs11.P11Cipher
Signature.SHA256withRSA=sun.security.pkcs11.P11Signature
KeyStore.PKCS11=sun.security.pkcs11.P11KeyStore
MessageDigest.MD5=sun.security.pkcs11.P11Digest
KeyPairGenerator.DSA=sun.security.pkcs11.P11KeyPairGenerator
SecretKeyFactory.DES=sun.security.pkcs11.P11SecretKeyFactory
MessageDigest.MD2=sun.security.pkcs11.P11Digest
Alg.Alias.SecretKeyFactory.RC4=ARCFOUR
SecureRandom.PKCS11=sun.security.pkcs11.P11SecureRandom
KeyAgreement.DH=sun.security.pkcs11.P11KeyAgreement
Alg.Alias.MessageDigest.SHA-1=SHA1
Provider.id info=SunPKCS11-SunPKCS11-rainbow_token usi...
Signature.DSA=sun.security.pkcs11.P11Signature
Signature.SHA1withRSA=sun.security.pkcs11.P11Signature
Signature.SHA384withRSA=sun.security.pkcs11.P11Signature
KeyFactory.DSA=sun.security.pkcs11.P11DSAKeyFactory
Provider.id className=sun.security.pkcs11.SunPKCS11
KeyPairGenerator.RSA=sun.security.pkcs11.P11KeyPairGenerator
Alg.Alias.Signature.SHA1withDSA=DSA
Signature.RawDSA=sun.security.pkcs11.P11Signature
Alg.Alias.KeyFactory.DiffieHellman=DH
Cipher.RSA/ECB/PKCS1Padding=sun.security.pkcs11.P11RSACipher
Alias: 26094dc8-70b4-491c-9c6f-4e9e1f4f86bc

Aug 7, 2009 12:45:11 PM com.sun.org.apache.xml.internal.security.Init init
SEVERE: Bad:
java.lang.NullPointerException
at org.apache.crimson.tree.ElementNode.getAttributeNodeNS(ElementNode.java:415)
at org.apache.crimson.tree.ElementNode.getAttributeNS(ElementNode.java:392)
at com.sun.org.apache.xml.internal.security.Init.init(Init.java:187)
at org.jcp.xml.dsig.internal.dom.DOMXMLSignature.<clinit>(DOMXMLSignature.java:63)
at org.jcp.xml.dsig.internal.dom.DOMXMLSignatureFactory.newXMLSignature(DOMXMLSignatureFactory.java:35)
at sig.Main.main(Main.java:193)
java.lang.NullPointerException
at org.apache.crimson.tree.ElementNode.getAttributeNodeNS(ElementNode.java:415)
at org.apache.crimson.tree.ElementNode.getAttributeNS(ElementNode.java:392)
at com.sun.org.apache.xml.internal.security.Init.init(Init.java:187)
at org.jcp.xml.dsig.internal.dom.DOMXMLSignature.<clinit>(DOMXMLSignature.java:63)
at org.jcp.xml.dsig.internal.dom.DOMXMLSignatureFactory.newXMLSignature(DOMXMLSignatureFactory.java:35)
at sig.Main.main(Main.java:193)
Exception in thread "main" java.lang.NullPointerException
at org.apache.crimson.tree.ElementNode.getAttributeNodeNS(ElementNode.java:415)
at org.jcp.xml.dsig.internal.dom.DOMReference.marshal(DOMReference.java:271)
at org.jcp.xml.dsig.internal.dom.DOMSignedInfo.marshal(DOMSignedInfo.java:216)
at org.jcp.xml.dsig.internal.dom.DOMXMLSignature.marshal(DOMXMLSignature.java:194)
at org.jcp.xml.dsig.internal.dom.DOMXMLSignature.sign(DOMXMLSignature.java:304)
at sig.Main.main(Main.java:196)
Java Result: 1
BUILD SUCCESSFUL (total time: 16 seconds)