fix(Pinpoint): Add null check for endpoint response (#2704)

* null check for endpoint response

* add empty check

* add null check for results

Author: changxu0306

aws-android-sdk-pinpoint/src/main/java/com/amazonaws/mobileconnectors/pinpoint/internal/event/EventRecorder.java

@@ -51,6 +51,7 @@
 import com.amazonaws.services.pinpoint.model.EventItemResponse;
 import com.amazonaws.services.pinpoint.model.EventsBatch;
 import com.amazonaws.services.pinpoint.model.EventsRequest;
+import com.amazonaws.services.pinpoint.model.ItemResponse;
 import com.amazonaws.services.pinpoint.model.PublicEndpoint;
 import com.amazonaws.services.pinpoint.model.PutEventsRequest;
 import com.amazonaws.services.pinpoint.model.PutEventsResult;
@@ -436,12 +437,28 @@ private void submitEventsAndEndpoint(final JSONArray eventArray,
     }
 
     private void processEndpointResponse(EndpointProfile endpoint, PutEventsResult resultResponse) {
-        final EndpointItemResponse endpointItemResponse = resultResponse
+        final Map<String, ItemResponse> results = resultResponse
                 .getEventsResponse()
-                .getResults()
+                .getResults();
+        if (results == null || results.isEmpty()) {
+            log.error("PutEventsResult is empty!");
+            return;
+        }
+
+        if (endpoint.getEndpointId().isEmpty()) {
+            log.error("EndpointId is missing!");
+            return;
+        }
+
+        final EndpointItemResponse endpointItemResponse = results
                 .get(endpoint.getEndpointId())
                 .getEndpointItemResponse();
-        if(202 == endpointItemResponse.getStatusCode()) {
+        if (endpointItemResponse == null) {
+            log.error("EndPointItemResponse is null!");
+            return;
+        }
+
+        if (202 == endpointItemResponse.getStatusCode()) {
             log.info("EndpointProfile updated successfully.");
         } else {
             log.error("AmazonServiceException occurred during endpoint update: " +