src/java.base/share/classes/java/lang/ClassNotFoundException.java

*** 57,66 ****
--- 57,67 ----
   */
  public class ClassNotFoundException extends ReflectiveOperationException {
      /**
       * use serialVersionUID from JDK 1.1.X for interoperability
       */
+      @java.io.Serial
       private static final long serialVersionUID = 9176873029745254542L;
  
      /**
       * Constructs a <code>ClassNotFoundException</code> with no detail message.
       */
*** 109,118 ****
--- 110,120 ----
      /**
       * Serializable fields for ClassNotFoundException.
       *
       * @serialField ex Throwable
       */
+     @java.io.Serial
      private static final ObjectStreamField[] serialPersistentFields = {
          new ObjectStreamField("ex", Throwable.class)
      };
  
      /*
*** 122,131 ****
--- 124,134 ----
       *
       * The getException and getCause method returns the private "ex" field
       * in the older implementation and ClassNotFoundException::cause
       * was set to null.
       */
+     @java.io.Serial
      private void readObject(ObjectInputStream s) throws IOException, ClassNotFoundException {
          ObjectInputStream.GetField fields = s.readFields();
          Throwable exception = (Throwable) fields.get("ex", null);
          if (exception != null) {
              setCause(exception);
*** 134,143 ****
--- 137,147 ----
  
      /*
       * To maintain compatibility with older implementation, write a serial
       * "ex" field with the cause as the value.
       */
+     @java.io.Serial
      private void writeObject(ObjectOutputStream out) throws IOException {
          ObjectOutputStream.PutField fields = out.putFields();
          fields.put("ex", super.getCause());
          out.writeFields();
      }