--- old/src/java.base/share/classes/java/util/EventObject.java	2019-08-27 17:28:55.426324386 -0700
+++ new/src/java.base/share/classes/java/util/EventObject.java	2019-08-27 17:28:55.218324386 -0700
@@ -38,6 +38,7 @@
 
 public class EventObject implements java.io.Serializable {
 
+    @java.io.Serial
     private static final long serialVersionUID = 5516075349620653480L;
 
     /**