Update searchlib/src/main/java/com/yahoo/searchlib/aggregation/Grouping.java
@@ -182,7 +182,7 @@ public class Grouping extends Identifiable {
*
* @param level the level to add
* @return this, to allow chaining
- * @throws NullPointerException ff <code>level</code> argument is null
+ * @throws NullPointerException if <code>level</code> argument is null
*/
public Grouping addLevel(GroupingLevel level) {
groupingLevels.add(Objects.requireNonNull(level));
