--- old/src/java.base/share/classes/java/nio/file/ClosedFileSystemException.java	2019-08-27 17:28:10.846324386 -0700
+++ new/src/java.base/share/classes/java/nio/file/ClosedFileSystemException.java	2019-08-27 17:28:10.654324386 -0700
@@ -35,6 +35,7 @@
 public class ClosedFileSystemException
     extends IllegalStateException
 {
+    @java.io.Serial
     static final long serialVersionUID = -8158336077256193488L;
 
     /**