--- old/src/java.base/share/classes/java/util/TooManyListenersException.java	2019-08-27 17:29:13.854324386 -0700
+++ new/src/java.base/share/classes/java/util/TooManyListenersException.java	2019-08-27 17:29:13.666324386 -0700
@@ -48,6 +48,7 @@
  */
 
 public class TooManyListenersException extends Exception {
+    @java.io.Serial
     private static final long serialVersionUID = 5074640544770687831L;
 
     /**