--- old/src/java.base/share/classes/java/net/UnknownHostException.java	2019-08-27 17:28:06.938324386 -0700
+++ new/src/java.base/share/classes/java/net/UnknownHostException.java	2019-08-27 17:28:06.766324386 -0700
@@ -35,6 +35,7 @@
  */
 public
 class UnknownHostException extends IOException {
+    @java.io.Serial
     private static final long serialVersionUID = -4639126076052875403L;
 
     /**