Stream13.java

Map<String, Map<Thing, Boolean>> consumerWithEachDeviceStatus = consumerList
        .stream()
        .flatMap(consumer -> consumer.getThings()
                .stream()
                .map(thing -> new AbstractMap.SimpleImmutableEntry<>(consumer.getName(), thing))
        )
        .collect(Collectors.groupingBy(entry -> entry.getKey(),
                Collectors.toMap(AbstractMap.SimpleImmutableEntry::getValue, entry -> entry.getValue().isRunning())));

System.out.println(consumerWithEachDeviceStatus);
//Output: {Bob={Thing(name=AgriFieldSensor)=true, Thing(name=EyeVirusDetector)=true, Thing(name=Bulb)=true, Thing(name=MotionDetector)=true}, Satti={Thing(name=AgriFieldSensor)=true, Thing(name=MotionDetector)=true}, Sri={Thing(name=EyeVirusDetector)=true, Thing(name=Bulb)=true}, Malli={Thing(name=Bulb)=true, Thing(name=MotionDetector)=true}}