Why is two last conditions do not verify? In IntelliJ seems to work fine.

package com.codegym.task.task08.task0815; import java.util.ArrayList; import java.util.Collections; import java.util.HashMap; /* Census */ public class Solution { public static HashMap<String, String> createMap() { HashMap<String, String> map = new HashMap<>(); map.put("Moldova", "Ian"); map.put("Romania", "Vladimir"); map.put("Greece", "Liuda"); map.put("Spain", "George"); map.put("Portugal", "Mauricio"); map.put("Italy", "Vladimir"); map.put("France", "Vladimir"); map.put("Russia", "Ivan"); map.put("Sweden", "John"); map.put("Ukraine", "Vladimir"); return map; } public static int getSameFirstNameCount(HashMap<String, String> map, String name) { ArrayList<String> list = new ArrayList<>(map.values()); ArrayList<Integer> list2 = new ArrayList<>(); for (String s : list) { list2.add(Collections.frequency(list, s)); } // System.out.println(list); // System.out.println(list2); // System.out.println(Collections.max(list2)); return Collections.max(list2); } public static int getSameLastNameCount(HashMap<String, String> map, String lastName) { ArrayList<String> list = new ArrayList<>(map.keySet()); ArrayList<Integer> list2 = new ArrayList<>(); for (String s : list) { list2.add(Collections.frequency(list, s)); } // System.out.println(list); // System.out.println(list2); // System.out.println(Collections.max(list2)); return Collections.max(list2); } public static void main(String[] args) { // getSameFirstNameCount(createMap(), ""); // getSameLastNameCount(createMap(), ""); } }