Linked List

 

Linked List:

Linked List Is part of collection framework and it is available in “java.util” package .

Linked List implements List, Deque, Cloneable, Serializable interfaces and extends Abstract Sequential List class.

Linked List class maintains insertion order.

Java LinkedList class can contain duplicate elements.

Manipulation with Linked List is faster than Array List because it internally uses doubly LinkedList, so no bit shifting required in memory. so entire memory will not effect.

A linked list consumes more memory because it uses doubly linked list it contains collection of nodes each node consists of 3 parts 1) previous node 2) data 3) next node

Doubly Linked List − Items can be navigated forward and backward way.

Java LinkedList class is non synchronized.

Linked is not thread safe you must explicitly synchronize concurrent modifications to the linked list in a multi-threaded environment.

Creation of LinkedList:

Syntax:

LinkedList <E> llist = new LinkedList<E>();

LinkedList <E> llist = new LinkedList <E>(int initialcapacity);

Here, E represents element data type

Methods of LinkedList:

Some of the important methods in linked list

offer(E e): this method is used to adds the specified element as the last element of a list.

offerFirst(E e): this method is used to inserts the specified element at the front of a list.

offerLast(E e): this method is used to inserts the specified element at the end of a list.

peek(): this method is used to retrieves the first element of a list

peekFirst(): this method is used to retrieves the first element of a list or returns null if a list is empty.

peekLast(): this method is used to retrieves the last element of a list or returns null if a list is empty.

poll(): this method is used to retrieves and removes the first element of a list.

pollFirst(): this method is used to retrieves and removes the first element of a list, or returns null if a list is empty.

pollLast(): this method is used to retrieves and removes the last element of a list, or returns null if a list is empty.

pop(): this method is used to pops an element from the stack represented by a list.

push(E e): this method is used to pushes an element onto the stack represented by a list.

Java Code:

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