import java.util.*;  

public class hashmapeg3{  

 public static void main(String args[]){  

   HashMap<Integer,String> map=new HashMap<Integer,String>();//Creating HashMap    

   map.put(1,"Cat");  //Put elements in Map  

   map.put(2,"Dog");    

   map.put(3,"Markhor");   

   map.put(4,"Peacock");   

   System.out.println("HashMap after put(): ");  

   for(Map.Entry m : map.entrySet()){    

    System.out.println(m.getKey()+" "+m.getValue());    

   }  

  // change element with key 2

    map.replace(2, "Wolf");

    System.out.println("HashMap using replace(): ");

       for(Map.Entry m : map.entrySet()){    

    System.out.println(m.getKey()+" "+m.getValue());    

   } 

}  

}

Hashmap<String, String> map = new HashMap<>();

map.put("Hello", "you");

map.replace("Hello", "World");

map.get("Hello"); // World