Understanding LinkedList Operations in Java

Table of Contents

1. Introduction
2. Understanding LinkedList in Java
   • What is LinkedList?
   • Key Methods of LinkedList
3. LinkedList vs ArrayList
4. LinkedList Methods Explained
   • add()
   • get()
   • remove()
   • printList()
5. Example Code and Explanation
6. Conclusion

Introduction

In this article, we will explore the LinkedList class in Java, a fundamental data structure that is part of the Java Collections Framework. LinkedLists provide a dynamic structure that efficiently handles operations such as inserting and deleting elements. While arrays in Java have fixed sizes, LinkedLists offer flexibility, making them an excellent choice in situations where dynamic data manipulation is needed.

This guide is aimed at Java developers who are familiar with basic programming concepts and are looking to dive deeper into collections like LinkedList.

Understanding LinkedList in Java

What is LinkedList?

A LinkedList is a doubly linked list that implements both the List and Deque interfaces in Java. It allows for the insertion and deletion of elements from both ends of the list. Unlike an ArrayList, a LinkedList allocates space dynamically, making it more efficient for frequently inserting and removing elements from the list.

Key Methods of LinkedList

LinkedList vs ArrayList

While both LinkedList and ArrayList implement the List interface, they serve different purposes due to their underlying structure. Here’s a comparison between the two:

LinkedList Methods Explained

add()

The add() method inserts elements into the LinkedList. It appends the element at the end of the list by default.

Here, three elements are added to the LinkedList.

get()

The get() method retrieves an element from the specified index. However, in the example code provided, this method is not explicitly used.

remove()

The remove() method deletes an element from the list. It can remove the element by index or by object value.

printList()

The printList() method, as implemented in the provided code, prints all the elements in a List:

This method iterates through the list and prints each element to the console.

Example Code and Explanation

Let’s break down the provided Java code, which demonstrates the use of both LinkedList and ArrayList:

Code Breakdown

1. Creating a LinkedList:
   
   Python

   LinkedList<String> list1 = new LinkedList<>();

   1	LinkedList<String> list1 = new LinkedList<>();

   
   This creates an empty LinkedList that stores strings.
2. Adding Elements to the LinkedList:
   
   Python

   list1.add("Chaand"); list1.add("Jai"); list1.add("Veeru");

   1 2 3

   list1.add("Chaand"); list1.add("Jai"); list1.add("Veeru");

   
   These lines add three elements to the LinkedList.
3. Creating and Populating an ArrayList:
   
   Python

   ArrayList<String> list2 = new ArrayList<>(); list2.add("StudyEasy"); list2.add("organization"); list2.add("team");

   1 2 3 4

   ArrayList<String> list2 = new ArrayList<>(); list2.add("StudyEasy"); list2.add("organization"); list2.add("team");

   
   Similarly, an ArrayList is created and three elements are added to it.
4. Printing the List:
   
   Python

   new Main().printList(list2);

   1	new Main().printList(list2);

   
   This line calls the printList() method, which prints the contents of list2 (the ArrayList).

Output:

Conclusion

LinkedLists are a crucial part of the Java Collections Framework, offering flexibility in dynamic data manipulation. The primary advantage of LinkedLists is their efficiency in adding and removing elements compared to ArrayList. While both structures have their strengths, it’s important to choose the right one based on your specific use case.

Understanding these key methods will help you master the use of LinkedList in Java and use them effectively in your applications.