code: private void addIssuerNameInternal(Object name, X500Principal principal) {
          if (issuerNames == null) {
              issuerNames = new HashSet<Object>();
          }
          if (issuerX500Principals == null) {
              issuerX500Principals = new HashSet<X500Principal>();
          }
          issuerNames.add(name);
          issuerX500Principals.add(principal);
      }
docs: A private method that adds a name (String or byte array) to the
  issuerNames criterion. The issuer distinguished
  name in the {@code X509CRL} must match at least one of the specified
  distinguished names.
  
  @param name the name in string or byte array form
  @param principal the name in X500Principal form
  @throws IOException if a parsing error occurs