--- old/src/java.base/share/classes/java/util/IllegalFormatFlagsException.java	2019-08-27 17:29:00.962324386 -0700
+++ new/src/java.base/share/classes/java/util/IllegalFormatFlagsException.java	2019-08-27 17:29:00.782324386 -0700
@@ -36,6 +36,7 @@
  */
 public class IllegalFormatFlagsException extends IllegalFormatException {
 
+    @java.io.Serial
     private static final long serialVersionUID = 790824L;
 
     private String flags;