Does this contain only a single message or multiple?

I agree that storeMessageInfo is probably better. The only thing I am confused abut is that D3941 that is already accepted defined this method as storeNotification. I think it is better for JNI classes to use the same method names as corresponding C++ methods. Should I then rename this method across entire diff stack? This question and concern also applies to your comment below since it probably asks to rename variable that is also already used in accepted diffs.

Argument facebook::jni::JString rawMessageInfoString is expected to carry string under 'messageInfos' key from notification JSON object. All notifications I examined in debugger carried list of JSON objects under 'messageInfos' key, but they were always one-element lists. Still I assumed it is better to implement notification parsing functionality in such a way that we assume it may contain multiple messages and iterate over this array. Therefore it would probably be better to rename this argument to rawMessageInfosString.

I will copy and paste an answer to similar question in corresponding iOS diff D4063

comm::SQLiteQueryExecutor::initialize(sqliteFilePathStdStr) is implemented with std::call_once semantics, so multiple call to initialization method do not perform unnecessary operations. On the other hand I understand it might be confusing. Probably we could extend SQLiteQueryExecutor API to check if it is already initialized or add a flag in NotificationService. What do you think?