Java – HashMap Iterator example

Example

In the previous tutorial we have seen different-2 ways to iterate a HashMap. In this example we are gonna see how to iterate a HashMap using Iterator and display key and value pairs. The steps we followed in the below example are as follows:
1) Create a HashMap and populate it with key-value pairs.
2) Get the Set of key-value pairs by calling entrySet() method.
3) Obtain the iterator for entry set.
4) Display the key & pairs using getKey() and getValue() methods of Map.Entry interface.

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

public class HashMapIteratorExample {
 
 public static void main(String[] args) {
 
    // Creating a HashMap of int keys and String values
    HashMap<Integer, String> hashmap = new HashMap<Integer, String>();
 
    // Adding Key and Value pairs to HashMap
    hashmap.put(11,"Value1");
    hashmap.put(22,"Value2");
    hashmap.put(33,"Value3");
    hashmap.put(44,"Value4");
    hashmap.put(55,"Value5");
 
    // Getting a Set of Key-value pairs
    Set entrySet = hashmap.entrySet();
 
    // Obtaining an iterator for the entry set
    Iterator it = entrySet.iterator();
 
    // Iterate through HashMap entries(Key-Value pairs)
    System.out.println("HashMap Key-Value Pairs : ");
    while(it.hasNext()){
       Map.Entry me = (Map.Entry)it.next();
       System.out.println("Key is: "+me.getKey() + 
       " & " + 
       " value is: "+me.getValue());
   }
 }
}

Output:

HashMap Key-Value Pairs : 
Key is: 33 &  value is: Value3
Key is: 55 &  value is: Value5
Key is: 22 &  value is: Value2
Key is: 11 &  value is: Value1
Key is: 44 &  value is: Value4