Sort Map By Collection Value Size (descending)

Sort Map By Collection Value Size (descending).md

Note: Add a new criteria to compare method if sizes are equal.

Map<X, Set<Y>> notSortedMap = ...

Map<X, Set<Y>> sortedMap = new TreeMap<>(new Comparator<X>() {
    @Override
    public int compare(X firstX, X secondX) {
        return Integer.valueOf(notSortedMap.get(secondX).size()).compareTo(Integer.valueOf(notSortedMap.get(firstX).size()));
    }
});

sortedMap.putAll(notSortedMap);