--- a/src/java.base/share/classes/sun/net/ftp/FtpProtocolException.java	Thu Aug 29 18:52:30 2019 -0400
+++ b/src/java.base/share/classes/sun/net/ftp/FtpProtocolException.java	Thu Aug 29 16:31:34 2019 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1994, 2009, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1994, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -32,6 +32,7 @@
  * @author      Jonathan Payne
  */
 public class FtpProtocolException extends Exception {
+    @java.io.Serial
     private static final long serialVersionUID = 5978077070276545054L;
     private final FtpReplyCode code;