Collections – List – ArrayList and LinkedList:
So far we have already discussed regarding Set and Map. In this article we are going to discuss regarding Lists. There are two types of Lists – ArrayList and LinkedList – (HashSet here and HashMap here)



Difference Between ArrayList and LinkedList: 

ArrayList LinkedList
ArrayList uses array to store the elements LinkedList uses doubly linked list to store the elements
ArrayList needs to know the size or it will re-create when it needs to grow LinkedList grows dynamically
ArrayList Manipulation is slow since it is an array LinkedList Manipulation is fast

When should we use ArrayList and When to use LinkedList:

  • When random access of elements are needed
  • If we know the size of array ahead so we can allocate the memory


  • When we need more insertions/deletions
  • When we do not know the size to be allocated

Example Program:

import java.util.List;
import java.util.LinkedList;
public class ListExample {
    public static void main(String args[]){
         List linkedList = new LinkedList();
        //Inserting into linkedlist
        for(int i=0; i<9; i++){
        //Reading from LinkedList
        for(Object l1: linkedList){
            System.out.print(l1+" ");     
        //finding an element in linkedlist
        for(int i=0; i<linkedList.size();i++){
        //Removing from List 
        //Reading from LinkedList after Removing
        for(Object l1: linkedList){
            System.out.print(l1+" ");     


 HashSet here
HashMap here


By Sri

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