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

*** 727,746 ****
--- 727,748 ----
       *  out.writeUTF(getId());
       * </pre>
       *
       * @return the instance of {@code Ser}, not null
       */
+     @java.io.Serial
      Object writeReplace() {
          return new Ser(Ser.CHRONO_TYPE, this);
      }
  
      /**
       * Defend against malicious streams.
       *
       * @param s the stream to read
       * @throws java.io.InvalidObjectException always
       */
+     @java.io.Serial
      private void readObject(ObjectInputStream s) throws ObjectStreamException {
          throw new InvalidObjectException("Deserialization via serialization delegate");
      }
  
      void writeExternal(DataOutput out) throws IOException {