Hashes.java

// Java program to illustrate 
// Java.util.HashMap 

import java.util.*;

public class Hashes {
 public static void main(String[] args) {

 HashMap<String, Integer> map = new HashMap<>();
 System.out.println(map);
 map.put("First", 10);
 map.put("Second", 30);
 map.put("Third", 20);
 System.out.println("Size of map is:- " + map.size());
 System.out.println(map);
 if (map.containsKey("vishal")) {
 Integer a = map.get("vishal");
 System.out.println("value for key" + " \"vishal\" is:- " + a);
 }
 sortByKey(map);
 sortByValue(map);
 map.clear();
 System.out.println(map);
 }

 public static void print(Map<String, Integer> map) {
 if (map.isEmpty()) {
 System.out.println("map is empty");
 } else {
 System.out.println(map);
 }
 }

 public static void sortByKey(Map<String, Integer> map) {
 // TreeMap to store values of HashMap 
 TreeMap<String, Integer> sorted = new TreeMap<>();

 // Copy all data from hashMap into TreeMap 
 sorted.putAll(map);
 System.out.println("After sorting by key");
 // Display the TreeMap which is naturally sorted 
 for (Map.Entry<String, Integer> entry : sorted.entrySet())
 System.out.println("Key = " + entry.getKey() + ", Value = " + entry.getValue());
 }

 public static void sortByValue(HashMap<String, Integer> map) {
 List<String> mapKeys = new ArrayList<>(map.keySet());
 List<Integer> mapValues = new ArrayList<>(map.values());
 Collections.sort(mapValues);
 Collections.sort(mapKeys);

 LinkedHashMap<String, Integer> sortedMap = new LinkedHashMap<>();

 Iterator<Integer> valueIt = mapValues.iterator();
 while (valueIt.hasNext()) {
 Integer val = valueIt.next();
 Iterator<String> keyIt = mapKeys.iterator();
 while (keyIt.hasNext()) {
 String key = keyIt.next();
 Integer comp1 = map.get(key);
 Integer comp2 = val;
 if (comp1.equals(comp2)) {
 keyIt.remove();
 sortedMap.put(key, val);
 break;
 }
 }
 }
 System.out.println("Map Sorted By Value");
 System.out.println(sortedMap);
 }
}