Java Sort Map by Value

Java Sort Map By Value

The following snippet works for any Type

static <K, V extends Comparable<? super V>> Map<K, V> sortByValue(Map<K, V> map) {
  return map.entrySet()
    .stream()
    .sorted(comparingByValue())
    .collect(toMap(Map.Entry::getKey, Map.Entry::getValue, (e1, e2) -> e1, LinkedHashMap::new));
}  

Reverse Order

static <K, V extends Comparable<? super V>> Map<K, V> sortByValue(Map<K, V> map) {
  return map.entrySet()
    .stream()
    .sorted(comparingByValue(reverseOrder()))
    .collect(toMap(Map.Entry::getKey, Map.Entry::getValue, (e1, e2) -> e1, LinkedHashMap::new));
}  

Complete Code with test!

import java.util.*;

import static java.lang.System.out;
import static java.util.Collections.reverseOrder;
import static java.util.Map.Entry.comparingByValue;
import static java.util.stream.Collectors.toMap;

public class MapUtil {

    public static <K, V extends Comparable<? super V>> Map<K, V> sortByValue(Map<K, V> map) {
        return map.entrySet()
            .stream()
            .sorted(comparingByValue())
            .collect(toMap(Map.Entry::getKey, Map.Entry::getValue, (e1, e2) -> e1, LinkedHashMap::new));
    }

    public static <K, V extends Comparable<? super V>> Map<K, V> sortByValueReverseOrder(Map<K, V> map) {
        return map.entrySet()
            .stream()
            .sorted(comparingByValue(reverseOrder()))
            .collect(toMap(Map.Entry::getKey, Map.Entry::getValue, (e1, e2) -> e1, LinkedHashMap::new));
    }

    public static void main(String[] args) {
        Map<Integer, String> unsortedMap = Map.of(
            1, "G",
            2, "J",
            3, "A",
            4, "Y",
            5, "N",
            6, "O");

        out.println(sortByValue(unsortedMap));
        out.println(sortByValueReverseOrder(unsortedMap));
    }

}