HashMap_00.java

import java.util.*;


class HashMap_00 {
   public static void main(String args[]) {
       //Creation
       HashMap<String, Integer> map = new HashMap<>();


       //Insertion
       map.put("India", 120);
       map.put("US", 30);
       map.put("China", 150);


       System.out.println(map);


       map.put("China", 180);
       System.out.println(map);




       //Searching
       if(map.containsKey("Indonesia")) {
           System.out.println("key is present in the map");
       } else {
           System.out.println("key is not present in the map");
       }


       System.out.println(map.get("China")); //key exists
       System.out.println(map.get("Indonesia")); //key doesn't exist


       //Iteration (1)
       for( Map.Entry<String, Integer> e : map.entrySet()) {
           System.out.println(e.getKey());
           System.out.println(e.getValue());
       }


       //Iteration (2)
       Set<String> keys = map.keySet();
       for(String key : keys) {
           System.out.println(key+ " " + map.get(key));
       }


       //Removing
       map.remove("China");
       System.out.println(map);


   }
}