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

*** 128,137 ****
--- 128,138 ----
          implements ChronoLocalDate, Serializable {
  
      /**
       * Serialization version.
       */
+     @java.io.Serial
      private static final long serialVersionUID = -305327627230580483L;
  
      /**
       * The underlying ISO local date.
       */
*** 717,726 ****
--- 718,728 ----
       * 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");
      }
  
      /**
*** 734,743 ****
--- 736,746 ----
       *  out.writeByte(get(DAY_OF_MONTH));
       * </pre>
       *
       * @return the instance of {@code Ser}, not null
       */
+     @java.io.Serial
      private Object writeReplace() {
          return new Ser(Ser.JAPANESE_DATE_TYPE, this);
      }
  
      void writeExternal(DataOutput out) throws IOException {