--- a/src/java.base/share/classes/java/util/ArrayDeque.java	Thu Aug 29 18:52:30 2019 -0400
+++ b/src/java.base/share/classes/java/util/ArrayDeque.java	Thu Aug 29 16:31:34 2019 -0700
@@ -1157,6 +1157,7 @@
         }
     }
 
+    @java.io.Serial
     private static final long serialVersionUID = 2340985798034038923L;
 
     /**
@@ -1168,6 +1169,7 @@
      * followed by all of its elements (each an object reference) in
      * first-to-last order.
      */
+    @java.io.Serial
     private void writeObject(java.io.ObjectOutputStream s)
             throws java.io.IOException {
         s.defaultWriteObject();
@@ -1192,6 +1194,7 @@
      *         could not be found
      * @throws java.io.IOException if an I/O error occurs
      */
+    @java.io.Serial
     private void readObject(java.io.ObjectInputStream s)
             throws java.io.IOException, ClassNotFoundException {
         s.defaultReadObject();