java - Sort List using Map, sort it by count -


i sort list(list) value(count), , after key(item). asu arraylist of string;

system.out.println(asu); [3100, 3100, 3100, 1029, 1029, 1029, 1029, 1029, 1029, 1029, 100, 100, 100, 100, 100, 2005, 2005, 2005, 2005, 2005, 2005, 2005, 400, 400, 400, 400, 202, 202, 10]  list<string> list = arraylist<>(); map<string, integer> counts = new hashmap<>(); // fill list values....  (string item:list) {     integer count = counts.get(item);     if (count == null) {         // first time have seen item, count should one.         count = 1;     } else {         // increment count one.         count = count + 1;     }     counts.put(item, count); }          collections.sort(asu, new comparator<string>() {                     @override                     public int compare(string left, string right) {                          return integer.compare(counts.get(left), counts.get(right));                     }                 }); system.out.println(asu); [10, 202, 202, 3100, 3100, 3100, 400, 400, 400, 400, 100, 100, 100, 100, 100,  1029, 1029, 1029, 1029, 1029, 1029, 1029, 2005, 2005, 2005, 2005, 2005, 2005, 2005,]

the result after should following(return value in list):

   system.out.println(asu);     [10, 202, 202, 3100, 3100, 3100, 400, 400, 400, 400, 100, 100, 100, 100, 100, 2005, 2005, 2005, 2005, 2005, 2005, 2005, 1029, 1029, 1029, 1029, 1029, 1029, 1029]

and please, not advice "treemap"

just modify comparator use counts first , key itself:

collections.sort(asu, new comparator<string>() {      @override     public int compare(string left, string right) {         int countcompare = counts.get(left).compareto(counts.get(right)));         if(countcompare != 0) {             return countcompare;         }         return left.compareto(right);     } });

i'm assuming sorting list no null values


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