Вроде логика правильная, но всё таки неверная((
package com.javarush.task.task18.task1805;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
/*
Сортировка байт
*/
public class Solution {
public static void main(String[] args) throws Exception {
ArrayList<Integer> list = new ArrayList<>();
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
FileInputStream inputStream = new FileInputStream(reader.readLine());
while (inputStream.available() > 0) {
list.add(inputStream.read());
}
inputStream.close();
Collections.sort(list);
for (int a = 0; a < list.size(); a++) {
if (list.get(a).equals(list.get(a++))) {
list.remove(a++);
a--;
}
}
for (int a = 0; a < list.size(); a++) {
System.out.println(list.get(a) + " ");
}
}
}