What is a ArrayDeque in Java?

An ArrayDeque (also known as an “Array Double Ended Queue”, pronounced as “ArrayDeck”) is a special kind of a growable array that allows us to add or remove an element from both sides. An ArrayDeque implementation can be used as a Stack (Last-In-First-Out) or a Queue(First-In-First-Out).

Is ArrayDeque thread-safe Java?

They are not thread-safe which means that in the absence of external synchronization, ArrayDeque does not support concurrent access by multiple threads. Null elements are prohibited in the ArrayDeque. ArrayDeque class is likely to be faster than Stack when used as a stack.

Is ArrayDeque a list?

So, it should have O(1) addition and removal of elements at the front and back, as well as O(1) access of elements based on the index. It is not that hard to imagine a setup that would work for this. It seems like ArrayDeque would be a natural choice for this. However, ArrayDeque does not implement List.

Does ArrayDeque accept null?

Array deques have no capacity restrictions; they grow as necessary to support usage. They are not thread-safe; in the absence of external synchronization, they do not support concurrent access by multiple threads. Null elements are prohibited.

What is difference between ArrayDeque and LinkedList?

The ArrayDeque class is the resizeable array implementation of the Deque interface, whereas the LinkedList class is the list implementation. LinkedList implements all optional list operations. null elements are allowed in the LinkedList implementation but not in the ArrayDeque implementation.

Why ArrayDeque is faster than LinkedList and stack?

ArrayDeque is more efficient than the LinkedList for add and remove operation at both ends and LinkedList implementation is efficient for removing the current element during the iteration. The LinkedList implementation consumes more memory than the ArrayDeque.

Why ArrayDeque is faster than LinkedList?

Why is ArrayDeque faster than queue?

There are multiple reasons to use ArrayDeque instead of Stack as ArrayDeque is a Doubly ended Queue implemented as an Array. So, it can grow relatively faster. If you do not plan to use syncronized stack, then ArrayDeque is probably better than Stack which is Thread safe(and hence slow).

Does ArrayDeque implement List?

ArrayDeque implements Iterable, Collection, Deque, and Queue (and Serializable, Cloneable); so no List, just Iterable.

Why ArrayDeque is faster than stack?

Why ArrayDeque is faster than stack and LinkedList?

How ArrayDeque is faster than LinkedList?

null elements are allowed in the LinkedList implementation but not in the ArrayDeque implementation. In terms of efficiency, ArrayDeque is more efficient than the LinkedList for add and remove operation at both ends. The best operation in a LinkedList implementation is removing the current element during the iteration.