Need help on validating certificate

Hi,

I have code which should validate a x509 certificate. But it doesnt work.

import java.io.FileInputStream;
import java.security.cert.CertPath;
import java.security.cert.CertPathValidator;
import java.security.cert.Certificate;
import java.security.cert.CertificateFactory;
import java.security.cert.PKIXCertPathValidatorResult;
import java.security.cert.PKIXParameters;
import java.security.cert.TrustAnchor;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.Collections;
import java.util.*;

public class MainClass {

public static void main(String args[]) throws Exception {
CertificateFactory cf = CertificateFactory.getInstance("X.509");
List mylist = new ArrayList();

FileInputStream in = new FileInputStream(args[0]);

X509Certificate c = (X509Certificate)cf.generateCertificate(in);
mylist.add(c);

CertPath cp = cf.generateCertPath(mylist);
//CertPath cp = cf.generateCertPath(in);

Certificate trust = cf.generateCertificate(in);
TrustAnchor anchor = new TrustAnchor((X509Certificate) trust, null);

PKIXParameters params = new PKIXParameters(Collections.singleton(anchor));
params.setRevocationEnabled(false);
CertPathValidator cpv = CertPathValidator.getInstance("PKIX");
PKIXCertPathValidatorResult result = (PKIXCertPathValidatorResult) cpv.validate(cp, params);
System.out.println(result);
}
}

But this gives me the following error:

Exception in thread "main" java.security.cert.CertificateException: Could not parse certificate: java.io.IOException: DerInputStream.getLength(): lengthTag=127, too big.
at sun.security.provider.X509Factory.engineGenerateCertificate(Unknown Source)
at java.security.cert.CertificateFactory.generateCertificate(Unknown Source)
at MainClass.main(MainClass.java:33)
Caused by: java.io.IOException: DerInputStream.getLength(): lengthTag=127, too big.
at sun.security.util.DerInputStream.getLength(Unknown Source)
at sun.security.util.DerValue.init(Unknown Source)
at sun.security.util.DerValue.(Unknown Source)

Can somebody please tell me what is the mistake I am doing. I need to validate a X509 DER certificate and if possible any certificate (PEM etc).

Please help.

Thanks & Regards,
Aruna.