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

@@ -105,10 +105,11 @@
         implements ChronoZonedDateTime<D>, Serializable {
 
     /**
      * Serialization version.
      */
+    @java.io.Serial
     private static final long serialVersionUID = -5261813987200935591L;
 
     /**
      * The local date-time.
      */

@@ -331,20 +332,22 @@
      *  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 {