code: public Date get(String name) throws IOException {
          if (name.equalsIgnoreCase(DATE)) {
              if (date == null) {
                  return null;
              } else {
                  return (new Date(date.getTime()));    // clone
              }
          } else {
              throw new IOException
                  ("Name not supported by InvalidityDateExtension");
          }
      }
docs: Get the attribute value.