src/java.base/share/classes/java/util/ArrayDeque.java

*** 1155,1164 ****
--- 1155,1165 ----
          } catch (CloneNotSupportedException e) {
              throw new AssertionError();
          }
      }
  
+     @java.io.Serial
      private static final long serialVersionUID = 2340985798034038923L;
  
      /**
       * Saves this deque to a stream (that is, serializes it).
       *
*** 1166,1175 ****
--- 1167,1177 ----
       * @throws java.io.IOException if an I/O error occurs
       * @serialData The current size ({@code int}) of the deque,
       * 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();
  
          // Write out size
*** 1190,1199 ****
--- 1192,1202 ----
       * @param s the stream
       * @throws ClassNotFoundException if the class of a serialized object
       *         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();
  
          // Read in size and allocate array