--- old/src/java.base/share/classes/java/nio/file/ClosedWatchServiceException.java	2019-08-27 17:28:11.302324386 -0700
+++ new/src/java.base/share/classes/java/nio/file/ClosedWatchServiceException.java	2019-08-27 17:28:11.138324386 -0700
@@ -35,6 +35,7 @@
 public class ClosedWatchServiceException
     extends IllegalStateException
 {
+    @java.io.Serial
     static final long serialVersionUID = 1853336266231677732L;
 
     /**