Stream7.java

// How to loop nested collection using lambda streams?
Set<Event> allActiveDeviceOperations = consumerList
        .stream()
        // 'flatMap' intermediate operation, here produces the stream of user Things(Devices)
        .flatMap(consumer -> consumer.getThings().stream())
        .filter(thing -> thing.isRunning())
        .flatMap(thing -> thing.getEvents().stream())
        .collect(Collectors.toSet());
System.out.println(allActiveDeviceOperations);
//Output : [Event(name=motionCaptured), Event(name=switchedOff), Event(name=switchedOn), Event(name=virusFound), Event(name=dryField)]