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

*** 39,48 ****
--- 39,49 ----
   * @see Locale
   * @since 1.7
   */
  public class IllformedLocaleException extends RuntimeException {
  
+     @java.io.Serial
      private static final long serialVersionUID = -5245986824925681401L;
  
      private int _errIdx = -1;
  
      /**