--- old/src/java.base/share/classes/java/nio/file/ReadOnlyFileSystemException.java	2019-08-27 17:28:18.470324386 -0700
+++ new/src/java.base/share/classes/java/nio/file/ReadOnlyFileSystemException.java	2019-08-27 17:28:18.314324386 -0700
@@ -35,6 +35,7 @@
 public class ReadOnlyFileSystemException
     extends UnsupportedOperationException
 {
+    @java.io.Serial
     static final long serialVersionUID = -6822409595617487197L;
 
     /**