public class HashMapComparatorTest {

    public static void main(String[] args) {

        HashMap<String, Double> map = new HashMap<String, Double>();
        ValueComparator bvc = new ValueComparator(map);
        TreeMap<String, Double> sorted_map = new TreeMap<String, Double>(bvc);

        map.put("A", 99.5);
        map.put("B", 67.4);
        map.put("C", 67.4);
        map.put("D", 67.3);
        map.put("E", 100.);

        System.out.println("unsorted map: " + map);

        sorted_map.putAll(map);

        System.out.println("results: " + sorted_map);
    }

}

class ValueComparator implements Comparator<String> {

    Map<String, Double> base;

    public ValueComparator(Map<String, Double> base) {
        this.base = base;
    }

    // Note: this comparator imposes orderings that are inconsistent with equals.
    public int compare(String a, String b) {
        if (base.get(a) >= base.get(b)) {
            return -1;
        } else {
            return 1;
        } // returning 0 would merge keys
    }
}

new Comparator<Map.Entry<String, Double>>() {
                @Override
                public int compare(Map.Entry<String, Double> e1,
                        Map.Entry<String, Double> e2) {
                    return e1.getValue().compareTo(e2.getValue());
                }
            }

class ValueComparator implements Comparator<String> {

    Map<String, Double> base;

    public ValueComparator(Map<String, Double> base) {
        this.base = base;
    }

    // Note: this comparator imposes orderings that are inconsistent with equals.
    public int compare(String a, String b) {
        if (base.get(a) >= base.get(b)) {
            return -1;
        } else {
            return 1;
        } // returning 0 would merge keys
    }
}

System.out.println(sorted_map.get("A"));

public int compare(String a, String b) {
        if (base.get(a) > base.get(b)) {
            return -1;
        } else if (base.get(a) == base.get(b)){
            return 0;
        } else{
            return 1;
        }
    }