PowenKo, Android, Tutorial 009-2, Array, HashMap

August 28, 2011   ·   0 Comments

How to sort a Map<Key, Value> on the values in Java?


I am relatively new to Java, and often find that I need to sort a Map on the values. Since the values are not unique, I find myself converting the keySet into an array, and sorting that array through array sort with a custom comparator that sorts on the value associated with the key. Is there an easier way?


answer is below.


package com.powenko.Tutorial_Fun_HashMap;

import java.util.Arrays;
import java.util.Comparator;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Set;

import android.app.Activity;
import android.os.Bundle;

public class Tutorial_Fun_HashMapActivity extends Activity {
    /** Called when the activity is first created. */
    public void onCreate(Bundle savedInstanceState) {

        Map<String, String> map = new HashMap<String, String>();

        map.put("Cde", "C");
        map.put("Abc", "A");
        map.put("Cbc", "Z");
        map.put("Dbc", "D");
        map.put("Bcd", "B");
        map.put("sfd", "Bqw");
        map.put("DDD", "Bas");
        map.put("BGG", "Basd");

        System.out.println(sort(map, new Comparator<String>() {
            public int compare(String o1, String o2) {
                    return o1.compareTo(o2);

        String t1=map.get("BGG");
        String t2=map.get("Abc");


    public static <K, V> Map<K,V> sort(Map<K, V> in, Comparator<? super V> compare) {
        Map<K, V> result = new LinkedHashMap<K, V>();
        V[] array = (V[])in.values().toArray();
        for(int i=0;i<array.length;i++)

        Arrays.sort(array, compare);
        for (V item : array) {
            K key= (K) getKey(in, item);
            result.put(key, item);
        return result;

    public static <K, V>  Object getKey(Map<K, V> in,V value)
       Set<K> key= in.keySet();
       Iterator<K> keyIterator=key.iterator();
       while (keyIterator.hasNext()) {
           K valueObject = (K) keyIterator.next();
                   return valueObject;
       return null;

sample code:


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