Question regarding LinkedList in Java

Question

When I was reading a book for SCJP, I came across the following paragraph.

A LinkedList is ordered by index position, like ArrayList, except that the elements are doubly-linked to one another. This linkage gives you new methods (beyond what you get from the List interface) for adding and removing from the beginning or end, which makes it an easy choice for implementing a stack or queue. Keep in mind that a LinkedList may iterate more slowly than an ArrayList, but it's a good choice when you need fast insertion and deletion..

What makes a LinkedList to iterate more slowly than an ArrayList ?

Answer 1

Here is an answer from stackoverflow that explains it pretty well:

https://stackoverflow.com/questions/716597/array-or-list-in-java-which-is-faster

Basically, the ArrayList is contiguous where the LinkedList is not. Incrementing to the next location in memory with the ArrayList is considered faster than jumping to the next location via a reference in LinkedList. Also, maintenance of the LinkedList would incur overhead to maintain two sets of references for a doubly linked list.

Answer 2

I haven't looked at these classes in Java but typically an array will be faster than a linked list because in a linked list the list is made up of a series of nodes which each of a "link" to the next node in the sequence. So when you ask for the 10th element it has to cycle through 10 elements to pull the one you want. In an array (unless I'm mistaken) calling for an element takes you straight to that element.