@salomonbrys Hi, it's not actually using a singleton. We have a Graph object for every city we support (5 of them) which has static information about the road network of that city. We have another class, call it TrafficUpdater, which gets live traffic data for one city and modifies the respective Graph. There are always 5 Graphs and 5 TrafficUpdaters — long-standing objects. How would you do DI of the specific Graph into the TrafficUpdater? Thanks!