Retrieve all the keys from HashMap in Java

import java.util.HashMap;
import java.util.Iterator;
import java.util.Set;
public class Demo {
	public static void main(String[] args) {
		HashMap<Integer, String>map = new HashMap<Integer, String>();
		map.put(10, "A");
		map.put(20, "B");
		map.put(30, "C");
		map.put(40, "D");
		map.put(50, "E");
		map.put(60, "F");
		map.put(70, "G");
		map.put(80, "H");
		Set<Integer>set = map.keySet();
		Iterator<Integer>i = set.iterator();
		while (i.hasNext()) {
			Integer res = i.next();
			System.out.println(res + ": " + map.get(res));
		}
	}
}