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Creating Streams

Create Java Stream​

Java Stream Creation is one of the most basic steps before considering the functionalities of the Java Stream. Below is the syntax given on how to declare Java Stream.

Syntax​

Stream<T> stream;

Here T is either a class, object, or data type depending upon the declaration.

Ways to create Streams​

  • Stream.empty()​

    public void streamEmpty() {
        Stream<String> streamOfArray = Stream.empty();
    }

  • Stream.of()​

    public void streamOf() {
        Stream<Integer> stream = Stream.of(1,2,3,4,5,6,7,8,9);
        stream.forEach(System.out::println);
    }

  • List.stream()​

    public void listStream() {
        List<Integer> list = new ArrayList<Integer>();

        for(int i = 1; i< 10; i++){
            list.add(i);
        }

        Stream<Integer> stream = list.stream();
        stream.forEach(System.out::println);
    }

  • Stream.of(Array)​

    public void streamOfArray() {
        Stream<Integer> stream = Stream.of( new Integer[]{1,2,3,4,5,6,7,8,9} );
        stream.forEach(System.out::println);
    }

  • Stream.builder()​

    public void streamBuilder() {
        Stream.Builder<String> builder = Stream.builder();

        Stream<String> stream = builder.add("Aaaa")
                .add("bbbb")
                .add("Cccc")
                .add("DcDd")
                .build();

        stream.forEach(System.out::println);
    }

  • Stream.generate()​

    public void streamGenerate() {
        Stream<Integer> randomNumbers = Stream
                .generate(() -> (new Random()).nextInt(100));

        randomNumbers.limit(20).forEach(System.out::println);
    }

  • Stream.iterate()​

    public void streamIterate() {
        // create a stream using iterate
        Stream<Integer> stream
                = Stream.iterate(1,
                i -> i <= 20, i -> i * 2);

        // print Values
        stream.forEach(System.out::println);
    }

  • StreamOfStringChars()​

    public void StreamOfStringChars() {
        IntStream stream = "12345_abcdefg".chars();
        stream.forEach(System.out::println);
    }

Running Examples​