LinkedList in Java

In Java, LinkedList is an implementation of the List interface that uses a doubly-linked list data structure to store elements. It provides methods for adding, removing, and accessing elements in the list, and can be used to implement stacks, queues, and other data structures.

Here's an example of how to use LinkedList in Java

import java.util.LinkedList;
public class LinkedListExample {
  public static void main(String[] args) {
    // Create a LinkedList of strings
    LinkedList<String> names = new LinkedList<>();
    // Add elements to the LinkedList
    names.add("Alice");
    names.add("Bob");
    names.add("Charlie");
    // Access elements in the LinkedList
    String firstPerson = names.getFirst(); // Alice
    String lastPerson = names.getLast(); // Charlie
    // Modify elements in the LinkedList
    names.set(1, "Brian"); // [Alice, Brian, Charlie]
    // Remove elements from the LinkedList
    names.removeLast(); // [Alice, Brian]
    // Iterate over the LinkedList using a for-each loop
    for (String name : names) {
      System.out.println(name);
    }
    // Clear the LinkedList
    names.clear(); // []
  }
}​

In this example, we create a LinkedList of strings called names and add three elements to it using the add() method. We then access elements in the LinkedList using the getFirst() and getLast() methods, and modify elements in the LinkedList using the set() method. We also remove an element from the LinkedList using the removeLast() method. We then iterate over the LinkedList using a for-each loop, and finally clear the LinkedList using the clear() method.

Note that LinkedList provides several other methods, such as addFirst(), addLast(), isEmpty(), size(), and toArray(), that can be used to manipulate and access elements in the LinkedList. Additionally, LinkedList can be used with any object type, including custom objects, by specifying the object type when creating the LinkedList.

However, it's worth noting that LinkedList has some performance drawbacks compared to other List implementations, such as ArrayList, due to its use of pointers and memory allocation. Therefore, it's generally recommended to use LinkedList only when a linked list data structure is specifically required, such as for implementing certain algorithms or data structures. For most use cases, ArrayList is usually a better choice due to its better performance characteristics.