Difference between List and Set in Java

Java Object Oriented Programming Programming

List and Set both interface belongs to the Collection framework. Both interfaces extend the Collection interface. They both are used to store a collection of objects as a single unit.

Before jdk1.2, we used to use Arrays, Vectors, and Hashtable for grouping objects as a single unit.

Sr. No.	Key	List	Set
1	Positional access	The list provides positional access of the elements in the collection.	Set doesn't provide positional access to the elements in the collection
2	Implementation	Implementation of List are ArrayList,LinkedList,Vector ,Stack	Implementation of a set interface is HashSet and LinkedHashSet
3	Duplicate	We can store the duplicate elements in the list.	We can’t store duplicate elements in Set
4	Ordering	List maintains insertion order of elements in the collection	Set doesn’t maintain any order
5	Null Element	The list can store multiple null elements	Set can store only one null element

Example of List

import java.util.List;
import java.util.ArrayList;
import java.util.LinkedList;
public class ListExample {
   public static void main(String[] args) {
      List<String> al = new ArrayList<String>();
      al.add("BMW");
      al.add("Audi");
      al.add("BMW");
      System.out.println("List Elements: ");
      System.out.print(al);
   }
}

Output

List Elements:
[BMW, Audi, BMW]

Example of Set

import java.util.Set;
import java.util.HashSet;
import java.util.TreeSet;
public class SetExample {
   public static void main(String args[]) {
      int count[] = {2, 4, 3, 5};
      Set<Integer> hset = new HashSet<Integer>();
      try{
         for(int i = 0; i<4; i++){
            hset.add(count[i]);
         }
         System.out.println(hset);
      }
      catch(Exception e){
         e.printStackTrace();
      }
   }
}