1 files changed, 4 insertions, 2 deletions
diff --git a/src/main/java/com/juick/service/component/SystemEvent.java b/src/main/java/com/juick/service/component/SystemEvent.java
index 749f6af8..f4e3ff90 100644
--- a/src/main/java/com/juick/service/component/SystemEvent.java
+++ b/src/main/java/com/juick/service/component/SystemEvent.java
@@ -17,6 +17,8 @@
 
 package com.juick.service.component;
 
+import javax.annotation.Nonnull;
+
 import com.juick.www.api.SystemActivity;
 import org.springframework.context.ApplicationEvent;
 
@@ -28,12 +30,12 @@ public class SystemEvent extends ApplicationEvent {
      * @param source the object on which the event initially occurred (never {@code null})
      * @param activity system activity
      */
-    public SystemEvent(Object source, SystemActivity activity) {
+    public SystemEvent(Object source, @Nonnull SystemActivity activity) {
         super(source);
         this.activity = activity;
     }
 
-    public SystemActivity getActivity() {
+    public @Nonnull SystemActivity getActivity() {
         return activity;
     }
 }