How to use Iterator to loop through the Map key set?

First, create a HashMap, which is to be iterated −

Map<String, String>map = new LinkedHashMap<>(); map.put("Jack","0"); map.put("Tim", "1"); map.put("David","2"); map.put("Tom", "3"); map.put("Kevin", "4");

Now, use Iterator to map through keyset −

Iterator iterator = map.keySet().iterator();

Iterate through all the pairs −

while (iterator.hasNext()) {    String resKey = (String) iterator.next();    System.out.println("Rank of " + resKey + " is " + map.get(resKey)); }

Example

 Live Demo

import java.util.Iterator; import java.util.LinkedHashMap; import java.util.Map; public class Demo {    public static void main(String[] args) {       Map<String, String>map = new LinkedHashMap<>();       map.put("Jack","0");       map.put("Tim", "1");       map.put("David","2");       map.put("Tom", "3");       map.put("Kevin", "4");       map.put("Jeff", "5");       map.put("Katie","6");       map.put("Steve", "7");       map.put("Andrew", "8");       map.put("Angelina", "9");       String str = (String) map.get("David");       System.out.println("Rank of David = " + str);       Iterator iterator = map.keySet().iterator();       while (iterator.hasNext()) {          String resKey = (String) iterator.next();          System.out.println("Rank of " + resKey + " is " + map.get(resKey));       }    } }

Output

Rank of David = 2 Rank of Jack is 0 Rank of Tim is 1 Rank of David is 2 Rank of Tom is 3 Rank of Kevin is 4 Rank of Jeff is 5 Rank of Katies is 6 Rank of Steve is 7 Rank of Andrew is 8 Rank of Angelina is 9