src/java.base/share/classes/sun/net/ftp/FtpLoginException.java

@@ -32,10 +32,11 @@
  * FTP login operation.
  *
  * @author      Jonathan Payne
  */
 public class FtpLoginException extends IOException {
+    @java.io.Serial
     private static final long serialVersionUID = 2218162403237941536L;
 
     public FtpLoginException(String s) {
         super(s);
     }