diff --git a/apps/cpman/app/src/main/java/org/onosproject/cpman/impl/message/DefaultControlMessageStore.java b/apps/cpman/app/src/main/java/org/onosproject/cpman/impl/message/DefaultControlMessageStore.java
index d4ffc9c..4d1b31f 100644
--- a/apps/cpman/app/src/main/java/org/onosproject/cpman/impl/message/DefaultControlMessageStore.java
+++ b/apps/cpman/app/src/main/java/org/onosproject/cpman/impl/message/DefaultControlMessageStore.java
@@ -28,7 +28,7 @@
 import org.onosproject.store.AbstractStore;
 import org.slf4j.Logger;
 
-import java.util.Collection;
+import java.util.Set;
 
 import static org.slf4j.LoggerFactory.getLogger;
 
@@ -46,7 +46,7 @@
 
     @Override
     public ControlMessageEvent updateStatsInfo(ProviderId providerId, DeviceId deviceId,
-                                                     Collection<ControlMessage> controlMessages) {
+                                                     Set<ControlMessage> controlMessages) {
 
         return new ControlMessageEvent(ControlMessageEvent.Type.STATS_UPDATE, controlMessages);
     }