If I need to group by a property in Java 8, I can do this:
// cars is of type List<Car>
cars.stream().collect(Collectors.groupingBy(Car::getModel));
But how can I group the cars list by a property (e.g. make) of model? I've tried doing something like this:
Map<Make, List<Car>> listOfCarsByMake = cars.stream().collect(Collectors.groupingBy(Car::getModel::getMake));