The Java programming language offers a rich set of data structures that make it easier for software developers to build Java applications. Understanding the difference between data structures in Java is crucial in order to improve your applications’ performance and efficiency.
ArrayList and LinkedList are two Java data structures that can both be used to store a list of objects. So what’s the difference between ArrayList and LinkedList in Java?
In this article, we’ll go over everything you need to know about the question of LinkedList vs. ArrayList.
Resizable arrays, also called dynamic arrays, are data structures that store elements in sequential order and whose size can be increased or decreased by adding or removing elements.
Below, we look at the efficiency of some common ArrayList operations:
Doubly linked lists are data structures that store elements in sequential order, with each element associated with a node in the list.
Each node contains a pointer to the next and previous nodes in the list so that you can easily traverse the list either backward or forwards.
Below, we look at the efficiency of some common LinkedList operations:
The most important difference between ArrayList and LinkedList is the distinction between contiguous and non-contiguous memory.
ArrayLists use contiguous memory. All elements in the ArrayList are located next to each other in the same memory space.
This is why retrieving an element from an ArrayList is so fast: given the location of the start of the ArrayList, you can know exactly where any element is located in memory.
LinkedLists, on the other hand, use non-contiguous memory. There is no guarantee that two elements “next” to each other in a LinkedList are actually physically close in memory.
This is why retrieving an element from a LinkedList is slower: you need to traverse the list using pointers, instead of automatically predicting where the element is located.
On another note, ArrayLists are better if you have strict memory constraints. Storing an ArrayList requires space for only the data itself.
Storing a LinkedList, however, requires space for the data as well as for the forwards and backward pointers, which can be a significant overhead.
This means that the use cases for ArrayLists and LinkedLists are different in practice:
For example, LinkedLists are commonly used to implement a queue in which elements are inserted and removed in FIFO (first in, first out) order.
New elements can be quickly added (or “pushed”) to the front of the list, as well as quickly removed (or “popped”) from the front.
Looking for more software development insights?Check out the Adservio blog for the latest news and updates.
If you’re looking for a Java software development partner, Adservio can help.
Our skilled team of IT professionals helps companies achieve digital excellence in use cases from application development to software delivery.
Get in touch with us today to discuss your business needs and objectives.