src/java.base/share/classes/java/net/ConnectException.java

@@ -32,10 +32,11 @@
  * remote address/port).
  *
  * @since   1.1
  */
 public class ConnectException extends SocketException {
+    @java.io.Serial
     private static final long serialVersionUID = 3831404271622369215L;
 
     /**
      * Constructs a new ConnectException with the specified detail
      * message as to why the connect error occurred.