diff --git a/core/api/src/main/java/org/onosproject/net/flow/DefaultFlowRule.java b/core/api/src/main/java/org/onosproject/net/flow/DefaultFlowRule.java
index c8f2e9c..e46d918 100644
--- a/core/api/src/main/java/org/onosproject/net/flow/DefaultFlowRule.java
+++ b/core/api/src/main/java/org/onosproject/net/flow/DefaultFlowRule.java
@@ -364,7 +364,7 @@
 
         @Override
         public FlowRule build() {
-            checkArgument(flowId != null || appId != null, "Either an application" +
+            checkArgument((flowId != null) ^ (appId != null), "Either an application" +
                     " id or a cookie must be supplied");
             checkNotNull(selector, "Traffic selector cannot be null");
             checkArgument(timeout != null || permanent != null, "Must either have " +