LinkedList in Java

LinkedList is a part of the Java Collection Framework and is present in the java.util package. It implements a doubly-linked list data structure where elements are not stored in contiguous memory. Each node contains three parts: the data, a reference to the next node, and a reference to the previous node

• Dynamic Size: LinkedList grows or shrinks dynamically at runtime.
• Maintains Insertion Order: Elements are stored in the order they are added.
• Allows Duplicates: Duplicate elements are allowed.
• Not Synchronized: By default, LinkedList is not thread-safe. To make Thread-safe use of Collections.synchronizedList().
• Efficient Insertion/Deletion: Adding or removing elements at the beginning or middle is faster compared to ArrayList.

import java.util.LinkedList;

public class Geeks {

    public static void main(String[] args){
        
        // Creating a LinkedList
        LinkedList<String> l = new LinkedList<String>();

        // Adding elements to the LinkedList using add() method
        l.add("One");
        l.add("Two");
        l.add("Three");
        l.add("Four");
        l.add("Five");

        System.out.println(l);
    }
}

[One, Two, Three, Four, Five]

Explanation:

• Creates an empty LinkedList of Strings.
• Adds elements "One" to "Five" using the add() method.
• Prints the LinkedList showing elements in insertion order: [One, Two, Three, Four, Five].

Note: LinkedList nodes cannot be accessed directly by index; elements must be accessed by traversing from the head.

Hierarchy of LinkedList

It implements the List and Deque interfaces, both of which are sub-interfaces of the Collection Interface.