ArrayList in Java vs. LinkedList in Java — What's the Difference?
By Tayyaba Rehman & Fiza Rafique — Published on February 10, 2024
ArrayList in Java is a resizable array with direct indexing, ideal for accessing elements. LinkedList, a doubly-linked list, excels in adding/removing elements, trading off slower random access.
Difference Between ArrayList in Java and LinkedList in Java
Table of Contents
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Key Differences
ArrayList in Java is a dynamic array, allowing for efficient random access and size changes. It stores elements in a contiguous memory location, enabling quick retrieval via index. However, resizing an ArrayList, particularly during insertion or deletion, can be costly due to the need to shift elements.
LinkedList in Java, on the other hand, implements a doubly-linked list. It enables swift insertions and deletions as it only involves updating node links. However, accessing elements is slower in a LinkedList as it requires sequential traversal from the head or tail to reach the desired element.
ArrayList in Java is generally preferred when there are more get/set operations, as these operations are O(1) complexity. Its performance degrades during insertion or removal from anywhere but the end of the list, due to shifting of elements.
LinkedList in Java is ideal for scenarios where frequent addition or deletion of elements is required. Each element, or node, contains two references - one for the next node and one for the previous, facilitating easy removals and additions.
ArrayList in Java maintains a contiguous block of memory, which can lead to better cache performance. However, it might require more memory due to capacity resizing. LinkedList, with its node-based structure, uses more memory per element due to the additional previous and next references.
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Comparison Chart
Internal Structure
Dynamic Array
Doubly-Linked List
Element Access
Direct Indexing (Fast)
Sequential Traversal (Slower)
Insertion/Deletion
Slower (due to shifting)
Faster (update links)
Memory Efficiency
More efficient (less space)
Less efficient (extra refs)
Preferred Use Case
Frequent read operations
Frequent add/remove operations
Compare with Definitions
ArrayList in Java
Provides fast retrieval via indices.
Retrieve the third element in an ArrayList using list.get(2).
LinkedList in Java
Accessing elements requires traversing the list.
To access the fifth element in a LinkedList, start from the beginning and move forward.
ArrayList in Java
Internally manages capacity growth.
An ArrayList expands its capacity when more elements are added beyond its initial size.
LinkedList in Java
Each element links to both previous and next.
In a LinkedList, adding a new element updates the links of its neighbors.
ArrayList in Java
ArrayList in Java dynamically adjusts its size.
ArrayList allows adding elements without worrying about size constraints.
LinkedList in Java
Does not require resizing.
LinkedList allows adding as many elements as needed without resizing.
ArrayList in Java
Inherits behaviors of a list.
ArrayList can be used wherever a List is required due to polymorphism.
LinkedList in Java
Supports list and deque operations.
Use LinkedList as a queue or a stack as well as a list.
ArrayList in Java
Supports iterators and for-each loops.
Iterate over an ArrayList using a for-each loop for simplicity.
LinkedList in Java
Quick addition and removal of elements.
Inserting a new element in a LinkedList is fast as it only involves updating links.
Common Curiosities
How does memory usage compare between ArrayList and LinkedList?
ArrayList is more memory-efficient, whereas LinkedList uses more memory due to additional node references.
What is a LinkedList in Java?
A doubly-linked list implementation of the List and Deque interfaces.
How do ArrayList and LinkedList handle large data sets?
ArrayList can be more efficient for large datasets with frequent reads, while LinkedList handles large datasets with frequent modifications better.
When to use LinkedList over ArrayList?
Use LinkedList for frequent insertions and deletions, and less concern for random access speed.
How does iteration performance compare between the two?
Iteration is generally faster in ArrayList due to contiguous memory allocation.
Can LinkedList be used as a stack or queue?
Yes, LinkedList can function as both a stack and a queue.
Does ArrayList allow duplicates?
Yes, ArrayList allows duplicate elements.
What is an ArrayList in Java?
A resizable array implementation of the List interface.
Can ArrayList and LinkedList be used interchangeably?
Yes, they can be used interchangeably in contexts requiring a List, but performance implications should be considered.
Does ArrayList support efficient removals from its middle?
No, removals from the middle of an ArrayList are less efficient due to element shifting.
When to use ArrayList over LinkedList?
Use ArrayList when you need fast random access and minimal insertions/deletions.
How does resizing work in ArrayList?
ArrayList automatically resizes, but it can be inefficient due to the need to copy elements to a new array.
Is LinkedList faster for adding elements?
Yes, LinkedList is generally faster for additions and deletions compared to ArrayList.
Does LinkedList allow null elements?
Yes, LinkedList permits null elements.
Are ArrayList and LinkedList thread-safe?
Neither ArrayList nor LinkedList is thread-safe; external synchronization is needed for multi-threaded use.
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Written by
Tayyaba RehmanTayyaba Rehman is a distinguished writer, currently serving as a primary contributor to askdifference.com. As a researcher in semantics and etymology, Tayyaba's passion for the complexity of languages and their distinctions has found a perfect home on the platform. Tayyaba delves into the intricacies of language, distinguishing between commonly confused words and phrases, thereby providing clarity for readers worldwide.
Co-written by
Fiza RafiqueFiza Rafique is a skilled content writer at AskDifference.com, where she meticulously refines and enhances written pieces. Drawing from her vast editorial expertise, Fiza ensures clarity, accuracy, and precision in every article. Passionate about language, she continually seeks to elevate the quality of content for readers worldwide.
