HashMap example

HashMap example

 package com.ram;

import java.util.HashMap;
import java.util.Iterator;

public class HashMapExample {
 public static void main(String[] args) {
  HashMap map = new HashMap();
  //Men's ATP rankings as of 2014
  map.put(1, "Nadal");
  map.put(2, "Djokovic");
  map.put(3, "Ferrer");
  map.put(4, "Murray");
  map.put(5, "Del Porto");
  map.put(6, "Federer");
  
  //Get the size of HashMap
  System.out.println("Size of of HashMap: "+map.size());
  
  //Returns value if key is present
  System.out.println(map.get(2));
  
  //Retrieve values from HashMap
  Iterator it = map.keySet().iterator();
  while(it.hasNext()){
   Integer key = it.next();
   System.out.println(map.get(key)+" rank is : "+key);
  }
  
  //Returns true if the value is present
  System.out.println(map.containsValue("Murray"));
  
  //Returns true if key is present
  System.out.println(map.containsKey(6));
  
  //Removes key and its corresponding value if the key is present
  System.out.println("Removed "+map.remove(3));
 
  //Removes all mappings from map
  map.clear();
 }
}

 

Execute HashMapExample class and you get the below output:
Size of of HashMap: 6
Djokovic
Nadal rank is : 1
Djokovic rank is : 2
Ferrer rank is : 3
Murray rank is : 4
Del Porto rank is : 5
Federer rank is : 6
true
true
Removed Ferrer