Fix an issue where NPE could be thrown when a request fails before timer starts (#3096)

Author: zoewangg

.changes/next-release/bugfix-AWSSDKforJavav2-6e30c31.json

@@ -0,0 +1,6 @@
+{
+    "category": "AWS SDK for Java v2", 
+    "contributor": "", 
+    "type": "bugfix", 
+    "description": "Fixed an issue where NPE could be thrown when a request failed before API call timer started"
+}

.idea/inspectionProfiles/AWS_Java_SDK_2_0.xml

@@ -111,7 +111,7 @@ private Exception translatePipelineException(RequestExecutionContext context, Ex
         // but before we called timeoutTracker.cancel(). Note that if hasExecuted() returns true, its guaranteed that
         // the timeout tracker has set the interrupt flag, and if it returns false, it guarantees that it did not and
         // will never set the interrupt flag.
-        if (context.apiCallTimeoutTracker().hasExecuted()) {
+        if (apiCallTimerExecuted(context)) {
             // Clear the interrupt flag. Since we already have an exception from the call, which may contain information
             // that's useful to the caller, just return that instead of an ApiCallTimeoutException.
             Thread.interrupted();
@@ -133,7 +133,7 @@ private RuntimeException handleInterruptedException(RequestExecutionContext cont
         if (e instanceof SdkInterruptedException) {
             ((SdkInterruptedException) e).getResponseStream().ifPresent(r -> invokeSafely(r::close));
         }
-        if (context.apiCallTimeoutTracker().hasExecuted()) {
+        if (apiCallTimerExecuted(context)) {
             // Clear the interrupt status
             Thread.interrupted();
             return generateApiCallTimeoutException(context);
@@ -143,6 +143,10 @@ private RuntimeException handleInterruptedException(RequestExecutionContext cont
         return AbortedException.create("Thread was interrupted", e);
     }
 
+    private static boolean apiCallTimerExecuted(RequestExecutionContext context) {
+        return context.apiCallTimeoutTracker() != null && context.apiCallTimeoutTracker().hasExecuted();
+    }
+
     private ApiCallTimeoutException generateApiCallTimeoutException(RequestExecutionContext context) {
         return ApiCallTimeoutException.create(
                 resolveTimeoutInMillis(context.requestConfig()::apiCallTimeout, apiCallTimeout));