HashMap in java

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
 
/**
 * This class is used to show the HashMap functionality.
 * @author w3spoint
 */
public class HashMapTest {
	public static void main(String args[]){
		//Create HashMap object.
		Map hashMap = new HashMap();
 
		//Add objects to the HashSet.
		hashMap.put(4, "Roxy");
		hashMap.put(2, "Sunil");
		hashMap.put(5, "Sandy");
		hashMap.put(1, "Munish");
		hashMap.put(3, "Pardeep");
 
		//Print the HashMap object.
		System.out.println("HashMap elements:");
		System.out.println(hashMap);
 
		//Get iterator
		Set set=hashMap.entrySet();  
		Iterator iterator=set.iterator();  
 
		//Print the HashMap elements using iterator.
		System.out.println("HashMap elements using iterator:");
		while(iterator.hasNext()){
		   Map.Entry mapEntry=(Map.Entry)iterator.next();  
		   System.out.println("Key: " + mapEntry.getKey() + ", " +
		   		"Value: " + mapEntry.getValue());  
		}  
	}
}

HashMap elements:
{1=Munish, 2=Sunil, 3=Pardeep, 4=Roxy, 5=Sandy}
HashMap elements using iterator:
Key: 1, Value: Munish
Key: 2, Value: Sunil
Key: 3, Value: Pardeep
Key: 4, Value: Roxy
Key: 5, Value: Sandy

import java.util.*;  
public class HashMapExample{  
 public static void main(String args[]){  
   HashMap<Integer,String> hm=new HashMap<Integer,String>();    
    System.out.println("The initial list of elements:: "+hm);  
      hm.put(200,"A");    
      hm.put(201,"B");    
      hm.put(202,"C");   
 
      System.out.println("After invoking the put() method:: ");  
      for(Map.Entry m:hm.entrySet()){    
       System.out.println(m.getKey()+" "+m.getValue());    
      }  
 
      hm.putIfAbsent(203, "D");  
      System.out.println("After invoking the putIfAbsent() method:: ");  
      for(Map.Entry m:hm.entrySet()){    
           System.out.println(m.getKey()+" "+m.getValue());    
          }  
      HashMap<Integer,String> map=new HashMap<Integer,String>();  
      map.put(204,"E");  
      map.putAll(hm);  
      System.out.println("After invoking the putAll() method:: ");  
      for(Map.Entry m:map.entrySet()){    
           System.out.println(m.getKey()+" "+m.getValue());    
          }  
 }  
}

import java.util.*;  
public class HashMapExample{  
   public static void main(String args[]) {  
    HashMap<Integer,String> map=new HashMap<Integer,String>();          
      map.put(200,"A");    
      map.put(201,"B");    
      map.put(202,"C");  
      map.put(203, "D");  
    System.out.println("The initial list of elements:: "+map);  
    //key-based removal  
    map.remove(200);  
    System.out.println("The updated list of elements:: "+map);  
    //value-based removal  
    map.remove(201);  
    System.out.println("The updated list of elements:: "+map);  
    //key-value pair based removal  
    map.remove(202, "C");  
    System.out.println("The updated list of elements:: "+map);  
   }      
}

import java.util.*;  
public class HashMapExample{  
 public static void main(String args[]){  
   HashMap<Integer,String> hm=new HashMap<Integer,String>();    
      hm.put(200,"A");    
      hm.put(201,"B");    
      hm.put(202,"C");   
      System.out.println("The initial list of elements::");  
     for(Map.Entry m:hm.entrySet())  
     {  
        System.out.println(m.getKey()+" "+m.getValue());   
     }  
     System.out.println("The updated list of elements::");  
     hm.replace(202, "c");  
     for(Map.Entry m:hm.entrySet())  
     {  
        System.out.println(m.getKey()+" "+m.getValue());   
     }  
     System.out.println("The updated list of elements::");  
     hm.replace(201, "B", "b");  
     for(Map.Entry m:hm.entrySet())  
     {  
        System.out.println(m.getKey()+" "+m.getValue());   
     }   
     System.out.println("The updated list of elements::");  
     hm.replaceAll((k,v) -> "a");  
     for(Map.Entry m:hm.entrySet())  
     {  
        System.out.println(m.getKey()+" "+m.getValue());   
     }  
 }  
}