src/java.base/share/classes/java/time/temporal/WeekFields.java

*** 240,249 ****
--- 240,250 ----
      public static final TemporalUnit WEEK_BASED_YEARS = IsoFields.WEEK_BASED_YEARS;
  
      /**
       * Serialization version.
       */
+     @java.io.Serial
      private static final long serialVersionUID = -1177360819670808121L;
  
      /**
       * The first day-of-week.
       */
*** 360,369 ****
--- 361,371 ----
       * @param s the stream to read
       * @throws InvalidObjectException if the serialized object has an invalid
       *     value for firstDayOfWeek or minimalDays.
       * @throws ClassNotFoundException if a class cannot be resolved
       */
+     @java.io.Serial
      private void readObject(ObjectInputStream s)
           throws IOException, ClassNotFoundException, InvalidObjectException
      {
          s.defaultReadObject();
          if (firstDayOfWeek == null) {
*** 380,389 ****
--- 382,392 ----
       * {@code firstDayOfWeek} and {@code minimalDays}.
       * @return the singleton WeekFields for the firstDayOfWeek and minimalDays.
       * @throws InvalidObjectException if the serialized object has invalid
       *     values for firstDayOfWeek or minimalDays.
       */
+     @java.io.Serial
      private Object readResolve() throws InvalidObjectException {
          try {
              return WeekFields.of(firstDayOfWeek, minimalDays);
          } catch (IllegalArgumentException iae) {
              throw new InvalidObjectException("Invalid serialized WeekFields: " + iae.getMessage());