code: private void setExtensions(Object val) throws CertificateException {
          if (version.compare(CertificateVersion.V3) < 0) {
              throw new CertificateException("Invalid version");
          }
          if (!(val instanceof CertificateExtensions)) {
            throw new CertificateException(
                               "Extensions class type invalid.");
          }
          extensions = (CertificateExtensions)val;
      }
docs: Set the extensions in the certificate.
  
  @params val the Object class value for the Extensions
  @exception CertificateException