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

*** 1257,1267 ****
          public Spliterator<Map.Entry<K,V>> spliterator() {
              return new EntrySpliterator<>(IdentityHashMap.this, 0, -1, 0, 0);
          }
      }
  
! 
      private static final long serialVersionUID = 8188218128353913216L;
  
      /**
       * Saves the state of the {@code IdentityHashMap} instance to a stream
       * (i.e., serializes it).
--- 1257,1267 ----
          public Spliterator<Map.Entry<K,V>> spliterator() {
              return new EntrySpliterator<>(IdentityHashMap.this, 0, -1, 0, 0);
          }
      }
  
!     @java.io.Serial
      private static final long serialVersionUID = 8188218128353913216L;
  
      /**
       * Saves the state of the {@code IdentityHashMap} instance to a stream
       * (i.e., serializes it).
*** 1270,1279 ****
--- 1270,1280 ----
       *          mappings) ({@code int}), followed by the key (Object) and
       *          value (Object) for each key-value mapping represented by the
       *          IdentityHashMap.  The key-value mappings are emitted in no
       *          particular order.
       */
+     @java.io.Serial
      private void writeObject(java.io.ObjectOutputStream s)
          throws java.io.IOException  {
          // Write out and any hidden stuff
          s.defaultWriteObject();
  
*** 1293,1302 ****
--- 1294,1304 ----
  
      /**
       * Reconstitutes the {@code IdentityHashMap} instance from a stream (i.e.,
       * deserializes it).
       */
+     @java.io.Serial
      private void readObject(java.io.ObjectInputStream s)
          throws java.io.IOException, ClassNotFoundException  {
          // Read in any hidden stuff
          s.defaultReadObject();