HashMap

package Collections;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Map.Entry;

public class Hashmap {
	
	
	public static void main(String[] args) {
		
		Map<Integer, String> h = new HashMap<Integer, String>();
		h.put(101,"alekha");
		h.put(102,"Chowdary");
		h.put(103,"Hari");
		h.put(104,"srikanth");
		h.put(103,"shekar");
		h.put(105, "alkeha");
		h.put(106, "shekar");
		h.put(null, null);
		System.out.println(h.get("Hari")); // if you are trying to get key through value gives null value 
		/*
		 * Iterator<Map.Entry<Integer, String>> itr = h.entrySet().iterator();
		 * 
		 * while(itr.hasNext()) { Map.Entry<Integer, String> entry = itr.next();
		 * System.out.println(entry.getKey() +" "+ entry.getValue());
		 * //System.out.println(entry.getValue());
		 * 
		 * }
		 */
		/*
		 * System.out.println(h.remove(105)); // remove particular key value
		 * System.out.println(h.containsKey(101));// boolean value
		 * System.out.println(h.containsValue("chowdary")); // boolean value
		 * System.out.println(h.isEmpty()); // boolean value
		 * System.out.println(h.size()); // return size of the map
		 * System.out.println(h.get(101)); h.clear(); System.out.println(h.size()); //
		 * after clear it returns size zero;
		 */
		/*
		 * for(Entry<Integer, String> entry:h.entrySet()) {
		 * System.out.println(entry.getKey()+" "+ entry.getValue()); }
		 */
		/*
		 * for(Integer it : h.keySet()) { System.out.println(it+" "); } for(String
		 * it:h.values()) { System.out.println(it+" "); }
		 */
		/*
		Map<Integer, String> s = new HashMap<>();
		s.put(987584888,"srilamshi");
		s.put(100000000,"Landline");
		s.put(100000001," mobile");
		s.put(857959955,"realme");
		s.putAll(h);
		
		Iterator<Map.Entry<Integer, String>> itr1 = s.entrySet().iterator();
		while(itr1.hasNext()) {
			Map.Entry<Integer,String> s1 = itr1.next();
			System.out.println(s1.getKey()+" "+ s1.getValue());
		}
	}
*/
		
	}
}