--- old/src/java.base/share/classes/java/lang/Enum.java	2019-08-27 17:27:09.334324386 -0700
+++ new/src/java.base/share/classes/java/lang/Enum.java	2019-08-27 17:27:09.042324386 -0700
@@ -275,11 +275,13 @@
     /**
      * prevent default deserialization
      */
+    @java.io.Serial
     private void readObject(ObjectInputStream in) throws IOException,
         ClassNotFoundException {
         throw new InvalidObjectException("can't deserialize enum");
     }
 
+    @java.io.Serial
     private void readObjectNoData() throws ObjectStreamException {
         throw new InvalidObjectException("can't deserialize enum");
     }