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

@@ -107,10 +107,11 @@
  * @since   1.2
  */
 public class ArrayList<E> extends AbstractList<E>
         implements List<E>, RandomAccess, Cloneable, java.io.Serializable
 {
+    @java.io.Serial
     private static final long serialVersionUID = 8683452581122892189L;
 
     /**
      * Default initial capacity.
      */

@@ -847,10 +848,11 @@
      * @throws java.io.IOException if an I/O error occurs
      * @serialData The length of the array backing the {@code ArrayList}
      *             instance is 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
         int expectedModCount = modCount;
         s.defaultWriteObject();

@@ -874,10 +876,11 @@
      * @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 {
 
         // Read in size, and any hidden stuff
         s.defaultReadObject();