Retrieve data from a Map reverse-ordered by value and then ordered by key

Problem

Given a Map of strings to their frequencies. Find top N-most frequent strings. If there is a tie get lexicographically smallest names first.

Solution

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List<String> findTopNNames(Map<String, Integer> data, int n) { Comparator<Map.Entry<String, Integer>> cmpByValueDesc = Map.Entry.comparingByValue(Comparator.reverseOrder()); Comparator<Map.Entry<String, Integer>> cmpByKey = Map.Entry.comparingByKey(); Comparator<Map.Entry<String, Integer>> cmp = cmpByValueDesc.thenComparing(cmpByKey); return data.entrySet().stream() .sorted(cmp) .map(Map.Entry::getKey) .limit(n) .collect(Collectors.toList()); }