List<Integer> integerList = new ArrayList<>();
        integerList.add(1);
        integerList.add(2);
        integerList.add(3);
        Stream<Integer> stream1 = integerList.stream();

        int[] array = {1,2,3};
        IntStream stream2 = Arrays.stream(array);

        Stream<Integer> stream3 = Stream.of(1,2,3);
        stream3.forEach(System.out::println);

        Stream<Integer> stream4 = Stream.iterate(1, n -> n + 1).limit(3);
        stream4.forEach(System.out::println);

        Stream<Double> stream5 = Stream.generate(Math::random).limit(3);
        stream5.forEach(System.out::println);

        try {
            Stream<String> stream6 = Files.lines(Paths.get("data.txt"), Charset.defaultCharset());
            stream6.forEach(System.out::println);
        } catch (IOException e) {
            e.printStackTrace();
        }