diff --git a/azure-client-runtime/src/main/java/com/microsoft/azure/TaskGroupBase.java b/azure-client-runtime/src/main/java/com/microsoft/azure/TaskGroupBase.java
index 5078b8caa66a8..8f178480c43be 100644
--- a/azure-client-runtime/src/main/java/com/microsoft/azure/TaskGroupBase.java
+++ b/azure-client-runtime/src/main/java/com/microsoft/azure/TaskGroupBase.java
@@ -165,8 +165,10 @@ public boolean isCancelled() {
          *
          * @param call the call
          */
-        private void addCall(ServiceCall<?> call) {
-            this.serviceCalls.add(call);
+        private void addCall(ServiceCall call) {
+            if (call != null) {
+                this.serviceCalls.add(call);
+            }
         }
     }
 }