Question

I just have a map implementation below to sort the values in descending order and I have used the below implementation.

public static Map<String,Integer> sortByComparator(Map<String,Integer> unsortMap) {

    List list = new LinkedList(unsortMap.entrySet());

    //sort list based on comparator
    Collections.sort(list, new Comparator() {
        public int compare(Object o1, Object o2) {
            return ((Comparable) ((Map.Entry) (o2)).getValue())
                    .compareTo(((Map.Entry) (o1)).getValue());
        }
    });

    //put sorted list into map again
    Map sortedMap = new LinkedHashMap();
    for (Iterator it = list.iterator(); it.hasNext();) {
        Map.Entry entry = (Map.Entry)it.next();
        sortedMap.put(entry.getKey(), entry.getValue());
    }
    return sortedMap;
}   

This does the necessary functions.. But I am curious to know whether I will be able to use tree map to sort this by descending order

Answer 1

You won’t, as the TreeMap sorts by key order, and you are sorting by value.