add @Override annotation

core/src/main/java/org/elasticsearch/indices/IndexingMemoryController.java

@@ -132,6 +132,7 @@ public class IndexingMemoryController extends AbstractComponent implements Index
         return threadPool.scheduleWithFixedDelay(statusChecker, interval);
     }
 
+    @Override
     public void close() {
         FutureUtils.cancel(scheduler);
     }