src/java.base/share/classes/java/time/zone/ZoneOffsetTransitionRule.java

@@ -165,10 +165,11 @@
      * @param offsetBefore  the offset before the cutover, not null
      * @param offsetAfter  the offset after the cutover, not null
      * @return the rule, not null
      * @throws IllegalArgumentException if the day of month indicator is invalid
      * @throws IllegalArgumentException if the end of day flag is true when the time is not midnight
+     * @throws IllegalArgumentException if {@code time.getNano()} returns non-zero value
      */
     public static ZoneOffsetTransitionRule of(
             Month month,
             int dayOfMonthIndicator,
             DayOfWeek dayOfWeek,

@@ -188,10 +189,13 @@
             throw new IllegalArgumentException("Day of month indicator must be between -28 and 31 inclusive excluding zero");
         }
         if (timeEndOfDay && time.equals(LocalTime.MIDNIGHT) == false) {
             throw new IllegalArgumentException("Time must be midnight when end of day flag is true");
         }
+        if (time.getNano() != 0) {
+            throw new IllegalArgumentException("Time's nano-of-second must be zero");
+        }
         return new ZoneOffsetTransitionRule(month, dayOfMonthIndicator, dayOfWeek, time, timeEndOfDay, timeDefnition, standardOffset, offsetBefore, offsetAfter);
     }
 
     /**
      * Creates an instance defining the yearly rule to create transitions between two offsets.