Определение числа с методом

import java.util.Scanner;
import java.util.ArrayList;
import java.io.*;
public class untitled {
    public static void main(String[] args) {
        boolean flag = true;
        Scanner in = new Scanner(System.in);
        System.out.print("Введите фразу: ");
        ArrayList<String> world = new ArrayList<>();
        ArrayList<String> result = new ArrayList<>();
        ArrayList<Integer> positions = new ArrayList<>();
        String phrase  = "";
        do {
            String str = in.nextLine();
            phrase = phrase + str+ " ";
            world.add(str);
            if(contains("end", str)){
                flag = false;
            }
        } while (flag);
        for (String phr:phrase.split(" ")) {
            if (numberFlag(phr)){
                result.add(phr);
                positions.add(phrase.indexOf(" "+phr)+1);
            }
        }
        for(String s: result){
            System.out.print(s + " ");
        }
        System.out.println();
        for (Integer i: positions){
            System.out.print(i + " ");
        }
    }

    public static boolean numberFlag (String line){
        String[] numbers = new String[]{"0", "1", "2", "3", "4", "5", "6", "7", "8", "9"};
        boolean  allNumber = true;
        boolean theNumber = false;
        for (String li :line.split("")) {
            theNumber = false;
            for (int i = 0; i < numbers.length; i++) {
                if (li.equals(numbers[i])) {
                    theNumber = true;
                }
            }
            if (!theNumber) {
                allNumber = false;
                break;
            }
        }
        return allNumber;
    }
    public static boolean contains (String end, String set){
        boolean flagEnd = false;
        for(String s: set.split(" ")) {
            if (set.equals(end)) {
                flagEnd = true;
            }
        }
        return flagEnd;
    }
}