Составить цепочку слов

package com.javarush.task.task22.task2209;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;

/*
Составить цепочку слов
*/
public class Solution {

    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        String fileName = reader.readLine();
        reader.close();
        BufferedReader fileReader = new BufferedReader(new FileReader(fileName));
        String line = "";
        while (fileReader.ready()) {
            line += fileReader.readLine()+ " ";
        }
        fileReader.close();
        StringBuilder result = getLine(line.split(" "));

        System.out.println(result.toString());
    }

    public static StringBuilder getLine(String... words) {
        if(words.length == 0) return new StringBuilder();
        ArrayList<String> list = new ArrayList<>();
        StringBuilder res = new StringBuilder();
        list.addAll(Arrays.asList(words));
        Collections.sort(list, new SortIgnoreCase());
        res.append(list.get(0) + " ");
        char first;
        char end;
        for(int j = 0;j < list.size();j++) {
            for (int y = j+1; y < list.size(); y++) {
                end = list.get(j).charAt(list.get(j).length() - 1);
                first = list.get(y).charAt(0);
                    if(String.valueOf(end).equalsIgnoreCase(String.valueOf(first))) {
                        res.append(list.get(y) + " ");
                        list.add(j+1,list.get(y));
                        list.remove(list.get(y));
                        break;
                    } else {
                        list.add(list.get(y));
                        list.remove(list.get(y));
                        if(y == list.size()-1) {
                            res.append(list.get(list.size()-1));
                            break;
                        }
                        y--;
                    }
            }
        }
        return res;
    }
    public static class SortIgnoreCase implements Comparator<Object> {
        public int compare(Object o1, Object o2) {
            String s1 = (String) o1;
            String s2 = (String) o2;
            return s1.toLowerCase().compareTo(s2.toLowerCase());
        }
    }
}