Jolly jumper sequence Another challenge from CodeEval that's causing me great pain...

Trying to find out if a sequence if a Jolly Jumper, which is 


  A sequence of n > 0 integers is called a jolly jumper if the absolute values of the difference between successive elements take on all the values 1 through n-1.


I ended up adapting this idea into this:

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class Main {

    public static void main(String[] args) throws IOException {
        //File file = new File(args[0]);
        File file = new File("test.txt");
        BufferedReader buffer = new BufferedReader(new FileReader(file));
        String line;
        while ((line = buffer.readLine()) != null) {
            line = line.trim();
            String[] numbersString = line.split(" ");
            int[] numbers = new int[numbersString.length];
            for (int i = 0; i &lt; numbers.length; i++){
                numbers[i] = Integer.parseInt(numbersString[i]);
            }
            System.out.println(isJolly(numbers));
        }
        System.exit(0);
    }

    public static String isJolly(int[] array) {
        List listResults = new ArrayList();
        for (int i = 0; i &lt; array.length - 1; i++) {
            int result = Math.abs(array[i] - array[i + 1]);
            if (result == 0) {
                return "Not jolly";
            }
            if (result &gt;= array.length) {
                return "Not jolly";
            }
            if (listResults.contains(result)) {
                return "Not jolly";
            }
            listResults.add(result);
        }
        return "Jolly";
    }
}


I tested it with a few examples locally and it worked, but when I submit the code I don't get any sequence to appear as jolly. What mistakes am I making?
As a simple comment, a function called isJolly should probably return a boolean. Then, the calling function can use that boolean to print either "Jolly" or "Not jolly".