Fix: null attribute check in decisionService and experimentUtils (#219)

Author: mnoman09

core-api/src/main/java/com/optimizely/ab/bucketing/DecisionService.java

@@ -348,7 +348,7 @@ void saveVariation(@Nonnull Experiment experiment,
     String getBucketingId(@Nonnull String userId,
                           @Nonnull Map<String, ?> filteredAttributes) {
         String bucketingId = userId;
-        if (filteredAttributes.containsKey(ControlAttribute.BUCKETING_ATTRIBUTE.toString())) {
+        if (filteredAttributes != null && filteredAttributes.containsKey(ControlAttribute.BUCKETING_ATTRIBUTE.toString())) {
             if (String.class.isInstance(filteredAttributes.get(ControlAttribute.BUCKETING_ATTRIBUTE.toString()))) {
                 bucketingId = (String) filteredAttributes.get(ControlAttribute.BUCKETING_ATTRIBUTE.toString());
                 logger.debug("BucketingId is valid: \"{}\"", bucketingId);

core-api/src/main/java/com/optimizely/ab/internal/ExperimentUtils.java

@@ -67,7 +67,7 @@ public static boolean isUserInExperiment(@Nonnull ProjectConfig projectConfig,
         }
 
         // if there are audiences, but no user attributes, the user is not in the experiment.
-        if (attributes.isEmpty()) {
+        if (attributes == null || attributes.isEmpty()) {
             return false;
         }