--- old/src/java.base/share/classes/java/time/chrono/HijrahChronology.java	2019-08-27 17:28:38.554324386 -0700
+++ new/src/java.base/share/classes/java/time/chrono/HijrahChronology.java	2019-08-27 17:28:38.354324386 -0700
@@ -205,6 +205,7 @@
     /**
      * Serialization version.
      */
+    @java.io.Serial
     private static final long serialVersionUID = 3127340209035924785L;
     /**
      * Singleton instance of the Islamic Umm Al-Qura calendar of Saudi Arabia.
@@ -1021,6 +1022,7 @@
      * @return the instance of {@code Ser}, not null
      */
     @Override
+    @java.io.Serial
     Object writeReplace() {
         return super.writeReplace();
     }
@@ -1031,6 +1033,7 @@
      * @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");
     }