Github user KanakaKumar commented on a diff in the pull request:
https://github.com/apache/carbondata/pull/1821#discussion_r162035296
--- Diff:
core/src/main/java/org/apache/carbondata/events/OperationListenerBus.java ---
@@ -57,9 +57,9 @@ public OperationListenerBus addListener(Class<? extends
Event> eventClass,
OperationEventListener operationEventListener) {
String eventType = eventClass.getName();
- List<OperationEventListener> operationEventListeners =
eventMap.get(eventType);
+ Set<OperationEventListener> operationEventListeners =
eventMap.get(eventType);
if (null == operationEventListeners) {
- operationEventListeners = new CopyOnWriteArrayList<>();
+ operationEventListeners = new CopyOnWriteArraySet<>();
--- End diff --
Insertion order of listeners is important. Please use LinkedHashSet
---
