AppendArrays SoftUni

import java.util.Arrays;
import java.util.Collections;
import java.util.List;
import java.util.Scanner;
import java.util.stream.Collectors;

public class AppendArrays {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        String input = scanner.nextLine(); //example input: "1 2 3 |4 5 6 |  7  8"
        List<String> list = Arrays.stream(input.split("\\|")).collect(Collectors.toList());
        Collections.reverse(list); //list elements are all symbols between the |
        // => reverse will reverse the whole elements, not the separate numbers
        // => the output is [  7  8, 4 5 6 , 1 2 3 ]

        System.out.println(list.toString().replaceAll("[\\[\\],]", "")
                .trim().replaceAll("\\s+", " "));
        //list.toString() -> "[  7  8, 4 5 6 , 1 2 3 ]"
        // replace [ -> "  7  8, 4 5 6 , 1 2 3 ]"
        // replace ] -> "  7  8, 4 5 6 , 1 2 3 "
        // replace , -> "  7  8 4 5 6  1 2 3 "
        //trim() -> "7  8 4 5 6  1 2 3"
        //replace more than one interval -> "7 8 4 5 6 1 2 3"
    }
}