How to iterate HashMap in Java

Iterate the Entry

// Java program to demonstrate iteration over
// Map.entrySet() entries using for-each loop

import java.util.Map;
import java.util.HashMap;

class IterationDemo
{
 public static void main(String[] arg)
 {
  Map<String,String> gfg = new HashMap<String,String>();

  // enter name/url pair
  gfg.put("GFG", "geeksforgeeks.org");
  gfg.put("Practice", "practice.geeksforgeeks.org");
  gfg.put("Code", "code.geeksforgeeks.org");
  gfg.put("Quiz", "quiz.geeksforgeeks.org");

  // using for-each loop for iteration over Map.entrySet()
  for (Map.Entry<String,String> entry : gfg.entrySet())
   System.out.println("Key = " + entry.getKey() +
       ", Value = " + entry.getValue());
 }
}

Iterate the key and value

// Java program to demonstrate iteration over
// Map using keySet() and values() methods

import java.util.Map;
import java.util.HashMap;

class IterationDemo
{
 public static void main(String[] arg)
 {
  Map<String,String> gfg = new HashMap<String,String>();

  // enter name/url pair
  gfg.put("GFG", "geeksforgeeks.org");
  gfg.put("Practice", "practice.geeksforgeeks.org");
  gfg.put("Code", "code.geeksforgeeks.org");
  gfg.put("Quiz", "quiz.geeksforgeeks.org");

  // using keySet() for iteration over keys
  for (String name : gfg.keySet())
   System.out.println("key: " + name);

  // using values() for iteration over values
  for (String url : gfg.values())
   System.out.println("value: " + url);
 }
}

Iterate over iterator

// Java program to demonstrate iteration over
// Map using keySet() and values() methods

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

class IterationDemo
{
 public static void main(String[] arg)
 {
  Map<String,String> gfg = new HashMap<String,String>();

  // enter name/url pair
  gfg.put("GFG", "geeksforgeeks.org");
  gfg.put("Practice", "practice.geeksforgeeks.org");
  gfg.put("Code", "code.geeksforgeeks.org");
  gfg.put("Quiz", "quiz.geeksforgeeks.org");

  // using iterators
  Iterator<Map.Entry<String, String>> itr = gfg.entrySet().iterator();

  while(itr.hasNext())
  {
   Map.Entry<String, String> entry = itr.next();
   System.out.println("Key = " + entry.getKey() +
        ", Value = " + entry.getValue());
  }
 }
}

Iterate over forEach

// Java code illustrating iteration
// over map using forEach(action) method

import java.util.Map;
import java.util.HashMap;

class IterationDemo
{
 public static void main(String[] arg)
 {
  Map<String,String> gfg = new HashMap<String,String>();

  // enter name/url pair
  gfg.put("GFG", "geeksforgeeks.org");
  gfg.put("Practice", "practice.geeksforgeeks.org");
  gfg.put("Code", "code.geeksforgeeks.org");
  gfg.put("Quiz", "quiz.geeksforgeeks.org");

  // forEach(action) method to iterate map
  gfg.forEach((k,v) -> System.out.println("Key = "
    + k + ", Value = " + v));

 }
}