Не проходит тест на время

package com.javarush.task.task18.task1803;

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.util.*;

/*
Самые частые байты
/home/masha/Desktop/txt.txt

*/

public class Solution {
    public static void main(String[] args) throws Exception {
        try (BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
             FileInputStream fileInputStream = new FileInputStream(reader.readLine());) {
            int b = -1;

            List<Byte> list = new ArrayList<>();
            Map<Integer, Byte> map = new HashMap<>();
            while ((b = fileInputStream.read()) != -1) {
                list.add((byte) b);
                map.put(Collections.frequency(list, (byte) b), (byte) b);

            }

            System.out.println(list);
            System.out.println(map);
        }

    }
}
вот вывод

[115, 105, 109, 112, 108, 101, 32, 116, 101, 120, 116, 32, 102, 111, 114, 32, 101, 120, 101, 109, 112, 108, 101, 32, 116, 101, 115, 116, 10]
{1=10, 2=115, 3=116, 4=116, 5=101, 6=101}

public static void main(String[] args) throws Exception {
        String string = "simple textt for exemple ttest";
        Map<Integer, Integer> myBytes = new HashMap<>();
        int maxTimes = 0;
        for (int ch : string.toCharArray()) {
            if (!myBytes.containsKey(ch)) {
                myBytes.put(ch, 1);
            } else {
                int tmpCounter = myBytes.get(ch) + 1;
                maxTimes = Math.max(tmpCounter, maxTimes);
                myBytes.put(ch, tmpCounter);
            }
        }
        for (Map.Entry<Integer, Integer> pair : myBytes.entrySet()) {
            if (pair.getValue() == maxTimes) {
                System.out.printf("%d ", pair.getKey());
            }
        }
    }