List vs map in java

• List stores only the value of the element.
• Map applies different mechanism as it stores value of the element along with a unique key associated to the each stored value.

• As List only stores the value of the element so it requires less memory space in comparison to Map.
• On other hand Map needs to store a unique key for each value so memory requirement increases.

• ArrayList, LinkedList and Vector implements List interface.
• HashMap, LinkedHashMap, TreeMap, etc. implements Map interface.

• List ensures that the insertion order is maintained.
• All Map implementations doesn’t guarantee of maintaining insertion order (if you care about order, useLinkedHashMap).

• Any number of null values can be stored in List.
• Only one null key is allowed in Map. But you can store any number of null values.

• List accepts duplicate values while storing.
• Map doesn’t accept duplicate Key. But duplicate values are allowed.

• In List elements can be retrieved specifying index of the element.
• In Map elements can be retrieved by specifying its Key.

import java.util.ArrayList;
import java.util.List;

public class SimpleArrayList {

      public static void main(String[] args) {
            //create Array List
            List

Example of Map

Given below is a simple example of hashmap in java:

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

public class MapExample {

        public static void main(String[] args) {

                        Map m = new HashMap

OUTPUT

Sonu Pandit
Technology geek, loves to write and share knowledge with the world. Having 10+ years of IT experience. B.Tech in Computer Science & Engineering