Get the CA Issuer URLs from a X509Cert in java

AIAFetcher.java

import java.io.IOException;
import java.io.InputStream;
import java.security.cert.CertificateException;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
import java.util.ArrayList;
import java.util.List;

import org.bouncycastle.asn1.ASN1Primitive;
import org.bouncycastle.asn1.x509.AccessDescription;
import org.bouncycastle.asn1.x509.AuthorityInformationAccess;
import org.bouncycastle.asn1.x509.Extension;
import org.bouncycastle.asn1.x509.GeneralName;
import org.bouncycastle.cert.jcajce.JcaX509ExtensionUtils;

public class AIAFetcher {

    public static void main(String[] args) throws IOException,
            CertificateException {
        try (InputStream certContents = AIAFetcher.class
                .getResourceAsStream("/somecert.cer")) {
            X509Certificate cert = (X509Certificate) CertificateFactory
                    .getInstance("X509").generateCertificate(certContents);

            List<String> caIssuers = getCaIssuers(cert);

            System.out.println(caIssuers);
        }
    }

    private static List<String> getCaIssuers(X509Certificate cert)
            throws IOException {
        List<String> caIssuers = new ArrayList<>();
        ASN1Primitive aiaDer = JcaX509ExtensionUtils.parseExtensionValue(
                cert.getExtensionValue(Extension.authorityInfoAccess.getId()));
        AuthorityInformationAccess aia = AuthorityInformationAccess
                .getInstance(aiaDer);
        for (AccessDescription desc : aia.getAccessDescriptions()) {
            if (desc.getAccessMethod()
                    .equals(AccessDescription.id_ad_caIssuers)) {
                GeneralName loc = desc.getAccessLocation();
                if (loc.getTagNo() == GeneralName.uniformResourceIdentifier)
                    caIssuers.add(loc.getName().toString());
            }
        }
        return caIssuers;
    }
}