Все ведь получается, результат показывает, че надо?
package com.javarush.task.task18.task1803;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.util.*;
/*
Максимальный байт
*/
public class Solution {
public static void main(String[] args) throws Exception {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
File nameFile = new File(reader.readLine());
FileInputStream fileInputStream = new FileInputStream(nameFile);
//HashMap<Integer, Integer> map = new HashMap<>();
ArrayList<Integer>list = new ArrayList<>();
while (fileInputStream.available() > 0){
list.add(fileInputStream.read());
//System.out.println(fileInputStream.read() + " ");
}
//byte[] bytes = new byte[(int)nameFile.length()];
//fileInputStream.read(list);
reader.close();
fileInputStream.close();
int maxRepeatingCount = Collections.frequency(list, list.get(0));
int repeatingByte = list.get(0);
for (int i = 0; i < list.size(); i++) {
if (Collections.frequency(list, list.get(i)) > maxRepeatingCount) {
maxRepeatingCount = Collections.frequency(list, list.get(i));
repeatingByte = list.get(i);
}
if (list.get(i).equals(repeatingByte)){
System.out.print(list.get(i) + " ");
}
}
}
}