Thread: map with duplicates - sort by value (duplicates disappear, but I need them)

Hi all,
I got map with full duplicates (key and value are duplicated). I need to sort the map by value, it sorts, but duplicates disappear and I need to keep them. Please see my code below. Thx for any suggestion.

package learn;
 
import java.util.IdentityHashMap;
import java.util.LinkedHashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.stream.Collectors;
 
public class sortMapWithDuplicates {
 
    private static Map<Integer, String> sortByValue(Map<Integer, String> unsortMap, final boolean order)
    {
        List<Entry<Integer, String>> list = new LinkedList<>(unsortMap.entrySet());
        System.out.println("check 1 - list = " + list);
        list.sort((o1, o2) -> order ? o1.getValue().compareTo(o2.getValue()) == 0
                ? o1.getKey().compareTo(o2.getKey())
                : o1.getValue().compareTo(o2.getValue()) : o2.getValue().compareTo(o1.getValue()) == 0
                ? o2.getKey().compareTo(o1.getKey())
                : o2.getValue().compareTo(o1.getValue()));
        System.out.println("check 2 - list sorted before return = " + list);
        return list.stream().collect(Collectors.toMap(Entry::getKey, Entry::getValue, (a, b) -> b, LinkedHashMap::new));
    }
 
	  public static void main(String[] args) {
		  Map<Integer, String> map = new IdentityHashMap<Integer, String>();
		  map.put(new Integer(1), "one");
		  map.put(new Integer(1), "one");
		  map.put(new Integer(2), "two");
		  map.put(new Integer(3), "three");
		  map.put(new Integer(4), "four");
		  System.out.println(sortByValue(map,true));
	  }
 
}

Console output:

check 1 - list = [1=one, 3=three, 2=two, 1=one, 4=four]
check 2 - list sorted before return = [4=four, 1=one, 1=one, 3=three, 2=two]
{4=four, 1=one, 3=three, 2=two}

As you can see, my two check steps show that duplicates are present, but they disappear on return.