src/java.base/share/classes/java/time/chrono/ChronoZonedDateTimeImpl.java

*** 105,114 ****
--- 105,115 ----
          implements ChronoZonedDateTime<D>, Serializable {
  
      /**
       * Serialization version.
       */
+     @java.io.Serial
      private static final long serialVersionUID = -5261813987200935591L;
  
      /**
       * The local date-time.
       */
*** 331,350 ****
--- 332,353 ----
       *  out.writeObject(getZone());
       * </pre>
       *
       * @return the instance of {@code Ser}, not null
       */
+     @java.io.Serial
      private Object writeReplace() {
          return new Ser(Ser.CHRONO_ZONE_DATE_TIME_TYPE, this);
      }
  
      /**
       * Defend against malicious streams.
       *
       * @param s the stream to read
       * @throws InvalidObjectException always
       */
+     @java.io.Serial
      private void readObject(ObjectInputStream s) throws InvalidObjectException {
          throw new InvalidObjectException("Deserialization via serialization delegate");
      }
  
      void writeExternal(ObjectOutput out) throws IOException {