src/java.base/share/classes/java/util/UnknownFormatConversionException.java

*** 34,43 ****
--- 34,44 ----
   *
   * @since 1.5
   */
  public class UnknownFormatConversionException extends IllegalFormatException {
  
+     @java.io.Serial
      private static final long serialVersionUID = 19060418L;
  
      private String s;
  
      /**