Java LinkedList

In this tutorial, we will learn about the LinkedList, its methods and how to implement it in Java.

LinkedList class implements Deque interface and itprovides us the functionality of LinkedList data structures which is a linear data structure where the elements are not stored in contiguous locations and every element is a separate object with a data part and address part. The elements are linked using pointers and addresses.

Constructors in the LinkedList

To use methods of an Vector class we have to create objects of Vector which can be done by the constructors of the LinkedList.There are four constructors present in Vector :

1. LinkedList(): This constructor is used to create an empty linked list. It can be created as:

   LinkedList ll = new LinkedList():;
   

2. LinkedList(Collection C): This constructor is used to create an ordered list which contains all the elements of a specified collection, as returned by the collection’s iterator.

   LinkedList ll = new LinkedList(C);
   

Methods of LinkedList

Example 1

import java.util.*; 

public class CodeMistic 
{ 

	public static void main(String args[]) 
	{ 
		// Creating object of the class linked list 
		LinkedList<String> ll = new LinkedList(); 

		// Adding elements to the linked list 
		ll.add("A"); 
		ll.add("B"); 
		ll.addLast("C"); 
		ll.addFirst("D"); 
		ll.add(2, "E"); 

		System.out.println(ll); 

		ll.remove("B"); 
		ll.remove(3); 
		ll.removeFirst(); 
		ll.removeLast(); 

		System.out.println(ll); 
	} 
} 


Output:

[D, A, E, B, C]                                                                                                                
[A] 

Example 2

// Java program to add elements to a LinkedList 
	
import java.util.*; 
	
public class CodeMistic 
{ 
	public static void main(String args[]) 
	{ 
		LinkedList<String> ll = new LinkedList<>(); 
	
		ll.add("You"); 
		ll.add("Using"); 
		ll.add(1, "Are"); 
		ll.add(3, "CodeMistic.");
		System.out.println(ll); 
	} 
} 


Output:

[You, Are, Using, CodeMistic.]

Example 3

// Java program to change elements in a LinkedList 
	
import java.util.*; 
	
public class CodeMistic 
{
	public static void main(String args[]) 
	{ 
		LinkedList<String> ll = new LinkedList<>(); 
	
		ll.add("I"); 
		ll.add("CodeMistic"); 
		ll.add(1, "Like"); 
	
		System.out.println("Initial LinkedList " + ll); 
	
		ll.set(1, "Love"); 
	
		System.out.println("Updated LinkedList " + ll); 
	} 
} 



Output:

Initial LinkedList [I, Like, CodeMistic]                                                                                       
Updated LinkedList [I, Love, CodeMistic]

Example 4

// Java program to remove elements in a LinkedList 
	
import java.util.*; 
	
public class CodeMistic 
{
	public static void main(String args[]) 
	{ 
		LinkedList<String> ll = new LinkedList<>(); 
	
		ll.add("I"); 
		ll.add("CodeMistic"); 
		ll.add(1, "Love"); 
	
		System.out.println( 
			"Initial LinkedList " + ll); 
	
		ll.remove(0); 
	
		System.out.println( 
			"After the Index Removal " + ll); 
	
		ll.remove("Love"); 
	
		System.out.println( 
			"After the Object Removal " + ll); 
	} 
} 


Output:

Initial LinkedList [I, Love, CodeMistic]                                                                                       
After the Index Removal [Love, CodeMistic]                                                                                     
After the Object Removal [CodeMistic]

Example 5

// Java program to iterate the elements in an LinkedList 
	
import java.util.*; 
	
public class CodeMistic 
{
	public static void main(String args[]) 
	{ 
		LinkedList<String> ll = new LinkedList<>(); 
	
		ll.add("I"); 
		ll.add("Using");
		ll.add("CodeMistic") 
		ll.add(1, "Love"); 
	
		// Using the Get method 
		for (int i = 0; i < ll.size(); i++) 
		{ 
	
			System.out.print(ll.get(i) + " "); 
		} 
	
		System.out.println(); 
	
		// Using the for each loop 
		for (String str : ll) 
			System.out.print(str + " "); 
	} 
} 
 


Output:

I Love Using CodeMistic                                                                                                        
I Love Using CodeMistic