diff --git a/core/java/android/net/IpSecManager.java b/core/java/android/net/IpSecManager.java
index 889e9bc787..2262a04647 100644
--- a/core/java/android/net/IpSecManager.java
+++ b/core/java/android/net/IpSecManager.java
@@ -853,6 +853,7 @@ public final class IpSecManager {
             return mResourceId;
         }
 
+        @NonNull
         @Override
         public String toString() {
             return new StringBuilder()