hashmapsort.java

package com.journaldev.programminginterviews;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;

public class SortHashMapByValue {

	public static void main(String[] args) {
		Map<String, Integer> scores = new HashMap<>();

		scores.put("David", 95);
		scores.put("Jane", 80);
		scores.put("Mary", 97);
		scores.put("Lisa", 78);
		scores.put("Dino", 65);

		System.out.println(scores);

		scores = sortByValue(scores);

		System.out.println(scores);

	}

	private static Map<String, Integer> sortByValue(Map<String, Integer> scores) {
		Map<String, Integer> sortedByValue = new LinkedHashMap<>();

		Set<Entry<String, Integer>> entrySet = scores.entrySet();
		System.out.println(entrySet);
	
		List<Entry<String, Integer>> entryList = new ArrayList<>(entrySet);
		System.out.println(entryList);

		entryList.sort((x, y) -> x.getValue().compareTo(y.getValue()));
		System.out.println(entryList);

		for (Entry<String, Integer> e : entryList)
			sortedByValue.put(e.getKey(), e.getValue());

		return sortedByValue;
	}

}