Main.java

package modern.challenge;

import java.util.Arrays;
import java.util.stream.IntStream;
import java.util.stream.Stream;

public class Main {

    public static void main(String[] args) {

        // String array
        String[] arr = {"One", "Two", "Three", "Four", "Five"};

        // array to Stream
        Stream<String> stream1 = Arrays.stream(arr);
        Stream<String> stream2 = Arrays.stream(arr, 0, 2);
        Stream<String> stream3 = Arrays.asList(arr).stream();
        Stream<String> stream4 = Arrays.asList(arr).subList(0, 2).stream();
        Stream<String> stream5 = Stream.of(arr);
        Stream<String> stream6 = Stream.of("One", "Two", "Three");

        // Stream to array
        String[] array1 = stream1.toArray(String[]::new);

        // integers array
        int[] integers = {2, 3, 4, 1};
        Integer[] boxedInt = {2, 3, 4, 1};

        IntStream intStream1 = Arrays.stream(integers);
        IntStream intStream2 = IntStream.of(integers);
        IntStream intStream3 = IntStream.range(0, integers.length);;
        IntStream intStream4 = IntStream.rangeClosed(0, integers.length);
        Stream<Integer> intStream5 = Stream.of(boxedInt);

        int[] intArray1 = intStream1.toArray();
        int[] intArray2 = intStream5.mapToInt(i -> i).toArray();
    }
}