How to Short Map By Values using Java 8

We can short a Map using java 8 and Java very easily let’s check out the code.

Shorting Map using Java 7

public static void main(String args[]) {
		Map<String, Integer> map = new HashMap<String, Integer>();
		map.put("Durgesh", 22);
		map.put("Amit", 10);
		map.put("Rajeev", 34);
		map.put("Sumanth", 99);
		map.put("Leonia", 43);
		
		sortAndPrintMapUsinglegacy(map);
	}

private static void sortAndPrintMapUsinglegacy(Map<String, Integer> map) {
		//Getting Entry Object of map to List so that we can sort them
		 List<Map.Entry<String, Integer>> entryList = new ArrayList(map.entrySet());
		 //Sorting the list by value
		 entryList.sort((o1,o2) ->{
			 //Sorting in ascending order of value
			 return o1.getValue() - o2.getValue(); 
		 });
		 //Creating a Linked Hashmap  so that insertion order will be maintained.
		 //As we need to maintain the sorted order as it is in list.
		 Map<String, Integer> finalMap = new LinkedHashMap<String, Integer>();
		 //Adding element from entrylist to linkedHashmap
		 for (Map.Entry<String, Integer> entry : entryList) {
			 finalMap.put(entry.getKey(), entry.getValue());
		 }
		 
		 //Printing the map
		 System.out.println(finalMap);
	}

Output of the above code is

{Amit=10, Durgesh=22, Rajeev=34, Leonia=43, Sumanth=99}

Shorting Map using Java 8

	
	public static void main(String args[]) {
		Map<String, Integer> map = new HashMap<String, Integer>();
		map.put("Durgesh", 22);
		map.put("Amit", 10);
		map.put("Rajeev", 34);
		map.put("Sumanth", 99);
		map.put("Leonia", 43);
		sortAndPrintMapUsingJava8(map);
	}

	private static void sortAndPrintMapUsingJava8(Map<String, Integer> map) {
		//Getting Entry Object of map to List so that we can sort them
		// and creating the stream of sorted sets
		 Map<String, Integer> finalMap = map.entrySet().stream()
				 		//Sorting in ascending order of value
						.sorted(Comparator.comparing(Map.Entry::getValue))
						//Creating a Linked Hashmap  so that insertion order will be maintained.
						 //As we need to maintain the sorted order as it is in list.
						 //Adding element from entrylist to linkedHashmap
						.collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, (x,y) -> y, LinkedHashMap::new));
		 //Printing the map
		 System.out.println(finalMap);			
		
	}

Here we used (x,y)->y which is mapper function which will map same value when keys are equal.

Output of the above code is

{Amit=10, Durgesh=22, Rajeev=34, Leonia=43, Sumanth=99}

Conclusion

Here we learned the ways of sorting HashMap on value using Java 8 and Legacy.