code: public void invoke(X509Certificate cert, GSIConstants.CertificateType certType) throws CertPathValidatorException {
          try {
              cert.checkValidity();
          } catch (CertificateExpiredException e) {
              throw new CertPathValidatorException(
                      "Certificate " + cert.getSubjectDN() + " expired", e);
          } catch (CertificateNotYetValidException e) {
              throw new CertPathValidatorException(
                      "Certificate " + cert.getSubjectDN() + " not yet valid.", e);
          }
      }
docs: Method that checks the time validity. Uses the standard Certificate.checkValidity method.
  
  @throws CertPathValidatorException If certificate has expired or is not yet valid.