--- old/src/java.base/share/classes/java/time/chrono/MinguoDate.java	2019-08-27 17:28:42.234324386 -0700
+++ new/src/java.base/share/classes/java/time/chrono/MinguoDate.java	2019-08-27 17:28:42.066324386 -0700
@@ -110,6 +110,7 @@
     /**
      * Serialization version.
      */
+    @java.io.Serial
     private static final long serialVersionUID = 1300372329181994526L;
 
     /**
@@ -481,6 +482,7 @@
      * @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");
     }
@@ -498,6 +500,7 @@
      *
      * @return the instance of {@code Ser}, not null
      */
+    @java.io.Serial
     private Object writeReplace() {
         return new Ser(Ser.MINGUO_DATE_TYPE, this);
     }