For line 301, I'd rather used the "", if there's no way there could be a null value. Correct me if i'm wrong, but if user will have <property name="logPackageBlacklist"></property>, wouldn't be the value then be just empty string "" ? If so, the check against empty string is perfectly fine and desired. I'll just add the null-check and remove the initialisation. For line 376, I'll also add the null-check for the blacklist, but not the whitelist.