LinkedList is a doubly linked list implementation of the List and Deque interfaces in Java.
It allows dynamic memory allocation, supports insertion and deletion efficiently, and maintains insertion order.

• Implements List, Deque, and Queue interfaces.
• Allows duplicate elements.
• Insertion and deletion are O(1) if reference is known.
• Provides methods like addFirst(), addLast(), removeFirst(), removeLast().

import java.util.*;

	public class LinkedListDemo {
	    public static void main(String[] args) {
	        LinkedList<String> list = new LinkedList<>();
	        list.add("Apple");
	        list.add("Banana");
	        list.addFirst("Mango");
	        list.addLast("Grapes");

	        System.out.println("First Element: " + list.getFirst());
	        System.out.println("All Elements: " + list);
	    }
	}

First Element: Mango  
All Elements: [Mango, Apple, Banana, Grapes]

• Higher memory usage (stores extra pointers for each node).
• Slower random access (O(n) compared to ArrayList’s O(1)).
• Not cache-friendly, as elements are scattered in memory.

• Access by index → O(n)
• Insert at head/tail → O(1)
• Delete at head/tail → O(1)

 When there are frequent insertions/deletions at the beginning/middle of the list, and random access is not a priority.