--- old/src/java.base/share/classes/sun/net/ftp/FtpLoginException.java	2019-08-27 17:29:29.490324386 -0700
+++ new/src/java.base/share/classes/sun/net/ftp/FtpLoginException.java	2019-08-27 17:29:29.322324386 -0700
@@ -34,6 +34,7 @@
  * @author      Jonathan Payne
  */
 public class FtpLoginException extends IOException {
+    @java.io.Serial
     private static final long serialVersionUID = 2218162403237941536L;
 
     public FtpLoginException(String s) {