diff -r 18863bf3501f -r e0b8b019d2f5 src/java.base/share/classes/java/util/PriorityQueue.java
--- a/src/java.base/share/classes/java/util/PriorityQueue.java	Thu Aug 29 18:52:30 2019 -0400
+++ b/src/java.base/share/classes/java/util/PriorityQueue.java	Thu Aug 29 16:31:34 2019 -0700
@@ -87,6 +87,7 @@
 public class PriorityQueue<E> extends AbstractQueue<E>
     implements java.io.Serializable {
 
+    @java.io.Serial
     private static final long serialVersionUID = -7720805057305804111L;
 
     private static final int DEFAULT_INITIAL_CAPACITY = 11;
@@ -755,6 +756,7 @@
      *             emitted (int), followed by all of its elements
      *             (each an {@code Object}) in the proper order.
      */
+    @java.io.Serial
     private void writeObject(java.io.ObjectOutputStream s)
         throws java.io.IOException {
         // Write out element count, and any hidden stuff
@@ -778,6 +780,7 @@
      *         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 {
         // Read in size, and any hidden stuff