--- old/src/java.base/share/classes/java/time/chrono/AbstractChronology.java	2019-08-27 17:28:35.774324386 -0700
+++ new/src/java.base/share/classes/java/time/chrono/AbstractChronology.java	2019-08-27 17:28:35.586324386 -0700
@@ -729,6 +729,7 @@
      *
      * @return the instance of {@code Ser}, not null
      */
+    @java.io.Serial
     Object writeReplace() {
         return new Ser(Ser.CHRONO_TYPE, this);
     }
@@ -739,6 +740,7 @@
      * @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");
     }