Dinesh on Java

• LinkedList class extends AbstractSequentialList and implements List, Deque and Queue interface.
• It can be used as List, stack or Queue as it implements all the related interfaces.
• It can contain duplicate elements and is not synchronized.
• maintains insertion order.
• not synchronized.
• No random access.
• manipulation fast because no shifting needs to be occurred.

The LinkedList class supports two constructors:

//The first constructor builds an empty linked list:
LinkedList( )

//The following constructor builds a linked list that is initialized with the elements of the collection c.
LinkedList(Collection c)

Example of LinkedList:

import java.util.*;

public class LinkedListDemo {

   public static void main(String args[]) {
      // create a linked list
      LinkedList ll = new LinkedList();
      // add elements to the linked list
      ll.add("F");
      ll.add("B");
      ll.add("D");
      ll.add("E");
      ll.add("C");
      ll.addLast("Z");
      ll.addFirst("A");
      ll.add(1, "A2");
      System.out.println("Original contents of ll: " + ll);

      // remove elements from the linked list
      ll.remove("F");
      ll.remove(2);
      System.out.println("Contents of ll after deletion: "
       + ll);
      
      // remove first and last elements
      ll.removeFirst();
      ll.removeLast();
      System.out.println("ll after deleting first and last: "
       + ll);

      // get and set a value
      Object val = ll.get(2);
      ll.set(2, (String) val + " Changed");
      System.out.println("ll after change: " + ll);
   }
}

output: