Fix NullPointerException (#1931)

* Fix nullpointerexceptions

* Drop telemetryItem when instrumentation key is null

* Add comments

* Better comments

* Update comment

Co-authored-by: Trask Stalnaker <[email protected]>

Co-authored-by: Trask Stalnaker <[email protected]>

Author: heyams

agent/agent-tooling/src/main/java/com/microsoft/applicationinsights/agent/internal/telemetry/TelemetryChannel.java

@@ -220,17 +220,22 @@ private CompletableResultCode internalSend(
                   error, endpointUrl.toString(), friendlyExceptionThrown, logger);
               operationLogger.recordFailure(
                   "Error sending telemetry items: " + error.getMessage(), error);
-              if (networkStatsbeat != null) {
+
+              // networkStatsbeat is null when it's sending a Statsbeat request.
+              // instrumentationKey is null when sending persisted file's raw bytes.
+              if (networkStatsbeat != null && instrumentationKey != null) {
                 networkStatsbeat.incrementRequestFailureCount(instrumentationKey);
               }
-              // sending raw bytes won't have any instrumentation key
+              // instrumentationKey is null when sending persisted file's raw bytes.
               if (instrumentationKey != null) {
                 writeToDiskOnFailure(byteBuffers);
               }
               result.fail();
             },
             () -> {
-              if (networkStatsbeat != null) {
+              // networkStatsbeat is null when it's sending a Statsbeat request.
+              // instrumentationKey is null when sending persisted file's raw bytes.
+              if (networkStatsbeat != null && instrumentationKey != null) {
                 networkStatsbeat.incrementRequestSuccessCount(
                     System.currentTimeMillis() - startTime, instrumentationKey);
               }
@@ -268,7 +273,9 @@ private void parseResponseCode(
       case 439: // Breeze-specific: THROTTLED OVER EXTENDED TIME
         // TODO handle throttling
         // TODO (heya) track throttling count via Statsbeat
-        if (networkStatsbeat != null) {
+        // networkStatsbeat is null when it's sending a Statsbeat request.
+        // instrumentationKey is null when sending persisted file's raw bytes.
+        if (networkStatsbeat != null && instrumentationKey != null) {
           networkStatsbeat.incrementThrottlingCount(instrumentationKey);
         }
         break;
@@ -281,7 +288,9 @@ private void parseResponseCode(
       case 0: // client-side exception
         // TODO exponential backoff and retry to a limit
         // TODO (heya) track failure count via Statsbeat
-        if (networkStatsbeat != null) {
+        // networkStatsbeat is null when it's sending a Statsbeat request.
+        // instrumentationKey is null when sending persisted file's raw bytes.
+        if (networkStatsbeat != null && instrumentationKey != null) {
           networkStatsbeat.incrementRetryCount(instrumentationKey);
         }
         break;