code: public void setCertificateValid(Date certValid) {
          if (certValid == null) {
              certificateValid = null;
          } else {
              certificateValid = (Date)certValid.clone();
          }
      }
docs: Sets the certificateValid criterion. The specified date must fall
  within the certificate validity period for the
  {@code X509Certificate}. If {@code null}, no certificateValid
  check will be done.
  <p>
  Note that the {@code Date} supplied here is cloned to protect
  against subsequent modifications.
  
  @param certValid the {@code Date} to check (or {@code null})
  @see #getCertificateValid