Java HashMap sort by value then key

Question

I am trying to sort a HashMap first by value (integer) then by key (string). The following method doesn't appear to be sorting the hashmap properly. Any ideas how to make it work properly ?

private static Map<String, Integer> sortHash(Map<String, Integer> map) {
 List<Map.Entry<String, Integer>> list = new ArrayList<>(map.entrySet());
 // Sort list by integer values then by string keys
 Collections.sort(list, (a, b) -> {
 int cmp1 = a.getValue().compareTo(b.getValue());
 if (cmp1 != 0)
 return cmp1;
 else
 return a.getKey().compareTo(b.getKey());
 });
 Map<String, Integer> result = new HashMap<>();
 for (Map.Entry<String, Integer> entry : list)
 result.put(entry.getKey(), entry.getValue());
 return result;
}

• Louis Wasserman: A better implementation of your comparator would be list.sort(Map.Entry.comparingByValue().thenComparing(Map.Entry.comparingByKey()))
• dimitris93: @LouisWasserman Would i have to call this after i initialize my list ? This is what I am seeing. Not sure what exactly I am missing.
• Egg Vans: Will you not have a problem where you are just putting your results into a HashMap which has no guaranteed order? I think you'll need to look at TreeMap and supply a comparator to that. See link

Answer 1

The issue is here:

Map<String, Integer> result = new HashMap<>();

Use LinkedHashMap since this map will maintain the order of the addition of the key/value pairs.