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

Java 8Object Oriented ProgrammingProgramming

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
raja
Published on 25-Apr-2019 09:28:37
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