src/java.base/share/classes/java/time/Duration.java

@@ -1368,10 +1368,11 @@
      *
      * @param unit the unit to truncate to, not null
      * @return a {@code Duration} based on this duration with the time truncated, not null
      * @throws DateTimeException if the unit is invalid for truncation
      * @throws UnsupportedTemporalTypeException if the unit is not supported
+     * @since 9
      */
     public Duration truncatedTo(TemporalUnit unit) {
         Objects.requireNonNull(unit, "unit");
         if (unit == ChronoUnit.SECONDS && (seconds >= 0 || nanos == 0)) {
             return new Duration(seconds, 0);