Three Groups

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Scanner;

public class Task {

    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);
        String[] strArray = scanner.nextLine().split("\\s+");
        int[] arr = new int[strArray.length];

        ArrayList<Integer> rem0 = new ArrayList<>();
        ArrayList<Integer> rem1 = new ArrayList<>();
        ArrayList<Integer> rem2 = new ArrayList<>();

        for (int i = 0; i < strArray.length; i++) {
            arr[i] = Integer.parseInt(strArray[i]);
            if (arr[i] % 3 == 0) {
                rem0.add(arr[i]);
            } else if (arr[i] % 3 == 1) {
                rem1.add(arr[i]);
            } else {
                rem2.add(arr[i]);
            }
        }
        System.out.println(rem0.toString().replace("[", "").replace("]", "").replace(",", ""));
        System.out.println(rem1.toString().replace("[", "").replace("]", "").replace(",", ""));
        System.out.println(rem2.toString().replace("[", "").replace("]", "").replace(",", ""));
    }
}