HashMap : put : Put a key, value mapping to the Map

public V put(K key, V value)

Associates the specified value with the specified key in this map.If the map previously contained a mapping for the key, the old value is replaced. Return the previous value associated with key, or null if there was no mapping for key.

import java.util.*;

class HashMapPut{
 public static void main(String args[]){
  HashMap<Integer, String> myMap;
  myMap = new HashMap<> ();
  
  /* Add Data to myMap */
  System.out.print("Putting 100 to myMap ");
  System.out.println(myMap.put(100, "Hi"));
  System.out.print("Putting 25 to myMap ");
  System.out.println(myMap.put(25, "How"));
  System.out.print("Putting 31 to myMap ");
  System.out.println(myMap.put(31, "Are"));
  System.out.print("Putting 100 to myMap ");
  System.out.println(myMap.put(100, "new String"));
  
  System.out.println("Elements in myMap are");
  System.out.println(myMap);
 }
}

Output

Putting 100 to myMap null
Putting 25 to myMap null
Putting 31 to myMap null
Putting 100 to myMap Hi
Elements in myMap are
{100=new String, 25=How, 31=Are}

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