Help with hashmap

Updated code same result:

package com.codegym.task.task18.task1804;

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

/*
Rarest bytes

*/

public class Solution {
    public static void main(String[] args) throws Exception {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        FileInputStream inStream = new FileInputStream(reader.readLine());
        ArrayList<Integer> list1 = new ArrayList<Integer>();
        ArrayList<Integer> list2 = new ArrayList<Integer>();
        while(inStream.available() > 0){

            int num = inStream.read();
            list1.add(num);
        }
        inStream.close();
        //System.out.println(list1.toString());
        HashMap<Integer,Integer> freqTable = new HashMap<Integer, Integer>();
        for (Integer i : list1) {
            Integer key = list1.get(i);

            freqTable.putIfAbsent(key,0);
            freqTable.put(key,freqTable.get(key)+1);

            if (freqTable.containsKey(key))
                freqTable.replace(key,freqTable.get(key)+1);
        }
        //System.out.println(freqTable);
        HashSet<Integer> minSet = new HashSet<Integer>();
        int minCounter = Integer.MAX_VALUE;
        Integer itemWithMinCounter = null;

        Iterator iterator = freqTable.entrySet().iterator();

        while (iterator.hasNext()){
            Map.Entry freqTableElement = (Map.Entry) iterator.next();
            int value = (int) freqTableElement.getValue();
            int key = (int) freqTableElement.getKey();
            if (value < minCounter){

                minCounter = value;
                itemWithMinCounter = key;
                minSet.add(key);


            }

            //System.out.println(minSet.toString());
        }
        for (Integer num : minSet){
            System.out.print(num+

1. line 33 and 34 is doing the same thing as line 31, you are incrementing the counter by 2 instead of 1 2. line 51 is incorrect. You are still iterating over the map to find the minimum counter. Only after you are done with the loop, minCounter has the correct value of minimum occurrences. Remove line 51. After the while loop, iterator over the map AGAIN, if the value is EQUAL to minCounter, print the key.

Thanks for your help fzw. Unfortunately, i am still not getting the picture. I will forgo this problem for a while and comeback to it after a bit of study. This is driving me mad.

This is my code public class Solution { public static void main(String[] args) throws Exception { BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); String filename = reader.readLine(); InputStream inputStream = new FileInputStream(filename); Map<Integer, Integer> countMap = new HashMap<>(); while (inputStream.available() > 0) { int data = inputStream.read(); countMap.put(data, countMap.getOrDefault(data, 0) + 1); } int frequency = findLeastFrequency(countMap); printLeastFrequent(countMap, frequency); reader.close(); inputStream.close(); } static int findLeastFrequency(Map<Integer, Integer> countMap) { int leastFrequency = Integer.MAX_VALUE; for (int frequency : countMap.values()) { leastFrequency = frequency < leastFrequency ? frequency : leastFrequency; } return leastFrequency; } static void printLeastFrequent(Map<Integer, Integer> countMap, int frequency) { for (Map.Entry<Integer, Integer> pair : countMap.entrySet()) { if (pair.getValue() == frequency) System.out.print(pair.getKey() + " "); } System.out.println(); } }