java linkedlist

Java LinkedList

In the previous chapter, you learned about the ArrayList class. The LinkedList class is

almost identical to the

ArrayList:

Example

// Import the LinkedList class

import java.util.LinkedList;



public class Main {

  public static void main(String[] args) {

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

    cars.add("Volvo");

    cars.add("BMW");

    cars.add("Ford");

    cars.add("Mazda");

    System.out.println(cars);

  }

}

Try it Yourself »

ArrayList vs. LinkedList

The LinkedList class is a collection which can contain many objects of the same type,

just like the ArrayList.

The LinkedList class has all of the same methods as the ArrayList class because

they both implement the List interface. This means that you can add items, change

items, remove items and clear the list in the same way.

However, while the ArrayList class and the LinkedList class can be used in the same way,

they are built very differently.

How the ArrayList works

The ArrayList class has a regular array inside it. When an element is added, it is placed

into the array. If the array is not big enough, a new, larger array is created to replace the

old one and the old one is removed.

How the LinkedList works

The LinkedList stores its items in "containers." The list has a link to the first container

and each container has a link to the next container in the list. To add an element to the list,

the element is placed into a new container and that container is linked to one of the other

containers in the list.

When To Use

It is best to use an ArrayList when:

You want to access random items frequently

You only need to add or remove elements at the end of the list

It is best to use a LinkedList when:

You only use the list by looping through it instead of accessing random

items

You frequently need to add and remove items from the beginning, middle or

end of the

LinkedList Methods

For many cases, the ArrayList is more efficient as it is common to need access to

random items in the list, but the LinkedList provides several methods to do certain

operations more efficiently: