Linkedlist java: Everything you need to know with code examples

Firstly, if you are a newbie to Java, one of the most essential things you should focus on is LinkedList java. However, which is this and how to perform it well? Then, in order to help you master it, ArrowHiTech will deliver you all useful information about Linkedlist Java and illustrate it through some specific code examples. So, if you’re about to Java, let’s explore right away! 

What is Linkedlist Java?

Firstly, Linkedlist Java is one of the parts of the Collection framework included in the java.util package. Then, this class implements the LinkedList data structure, which is a linear data structure in which the components are not stored in sequential order and each element is a separate object having a data and address part. Besides, pointers and addresses are used to connect the elements. 

Java

Firstly, every element is referred to as a node. What’s more, they are preferable over arrays because of their dynamic nature and ease of insertions and removals. However, it also comes with a few drawbacks, such as the fact that nodes cannot be reached immediately. So, instead, we must start at the top and follow the link to the desired node.

Now, coming to the following example to examine how to generate Linkedlist java:

import java.util.*;

public class Test {

public static void main(String args[])

{

// Creating object of the

// class linked list

LinkedList<String> ll

= new LinkedList<String>();

// 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);

}

}

After that, you will get the output like below:

[D, A, E, B, C]

[A]

Also read: Singly linked list java: Implementation with code examples

How to perform Various Operations on Linkedlist Java?

#1. Linkedlist java code to add elements

Firstly, you have to utilize the add(method) to know the way to add an element to an ArrayList. In particular, this method is overloaded with the ability to do several operations based on various arguments. Then, they are as follows:

  • add(Object): Firstly, it is used to add a new element to the LinkedList java at the end.
  • add(int index, Object): Secondly, this function is used to add an element to the LinkedList at a given index.

So, let’s explore the Linkedlist Java code below:

// Java program to add elements

// to a LinkedList

import java.util.*;

public class GFG {

public static void main(String args[])

{

LinkedList<String> ll = new LinkedList<>();

ll.add(“Geeks”);

ll.add(“Geeks”);

ll.add(1, “For”);

System.out.println(ll);

}

}

As a result, the output you receive will be like:

[Geeks, For, Geeks]

#2. Linkedlist java code to change elements

As soon as you add elements, you need to move to the step of changing elements. Also, to change something about the element, we can use the set() method. The element we want to update is referred to by the index of the element because a LinkedList is indexed. As a result, this method requires an index as well as the modified element to be inserted at that index. Then, let’s have a glance at following instance:

// Java program to change elements

// in a LinkedList

import java.util.*;

public class GFG {

public static void main(String args[])

{

LinkedList<String> ll = new LinkedList<>();

ll.add(“Geeks”);

ll.add(“Geeks”);

ll.add(1, “Geeks”);

System.out.println(“Initial LinkedList ” + ll);

ll.set(1, “For”);

System.out.println(“Updated LinkedList ” + ll);

}

}

After that, it will appear the outcome like:

Initial LinkedList [Geeks, Geeks, Geeks]

Updated LinkedList [Geeks, For, Geeks]

#3. Linkedlist java code to remove elements

Firstly, the remove() method can be used to delete an element from a LinkedList. In reality, this method is overloaded with the ability to do several operations based on various arguments. So, let’s check them below:

  • remove(Object): Firstly, it is applied to delete an object from the LinkedList Java. Then, if there are numerous instances of the same item, the first one is eliminated.
  • remove(int index): Because a LinkedList is indexed, remove(int index) takes an integer value. Moreover, it removes the element at that exact position from the LinkedList. Following the removal of one element, all other elements are moved to the left to cover the empty space, and the object indices are updated.

The program below will show you more specifically about Linkedlist java code in this step:

// Java program to remove elements

// in a LinkedList

import java.util.*;

public class GFG {

public static void main(String args[])

{

LinkedList<String> ll = new LinkedList<>();

ll.add(“Geeks”);

ll.add(“Geeks”);

ll.add(1, “For”);

System.out.println(

“Initial LinkedList ” + ll);

ll.remove(1);

System.out.println(

“After the Index Removal ” + ll);

ll.remove(“Geeks”);

System.out.println(

“After the Object Removal ” + ll);

}

}

Then, you will gain the following outcome:

Initial LinkedList [Geeks, For, Geeks]

After the Index Removal [Geeks, Geeks]

After the Object Removal [Geeks]

#4. Iterating the LinkedList Java

Firstly, it is possible to iterate through LinkedList Java in a variety of ways. Moreover, the basic for loop in combination with a get() method to acquire the element at a given index and the sophisticated for loop are the most well-known methods.

So, you should refer to the Linkedlist java code example below to understand more:

// Java program to iterate the elements

// in an LinkedList

import java.util.*;

public class GFG {

public static void main(String args[])

{

LinkedList<String> ll

= new LinkedList<>();

ll.add(“Geeks”);

ll.add(“Geeks”);

ll.add(1, “For”);

// Using the Get method and the

// for loop

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 + ” “);

}

}

Then, it will display the output like:

Geeks For Geeks 

Geeks For Geeks

Linkedlist java

Firstly, as you can see, AbstractList, CopyOnWriteArrayList, and AbstractSequentialList are the classes that implement the list interface in the diagram above. Also, each of the above-mentioned classes has its own set of features. Then, they are as follows:

  • AbstractList: It is adapted to implement an immutable list, and all that is required is to extend it and implement only the get() and size() functions.
  • CopyOnWriteArrayList: Firstly, this class runs the list interface. Besides, it’s an improved version of ArrayList in which all changes such as: add, set, delete, and so on, are made by creating a new copy of the list.
  • AbstractSequentialList: Firstly, the Collection interface and the AbstractCollection class are implemented by this class. Moreover, an unmodifiable list can be implemented by this class, and all that is required is to extend it and implement only the get() and size() functions.

How Linkedlist java work internally?

First and foremost, because a LinkedList java functions as a dynamic array and we don’t have to define the size when we create it, the list’s size grows as we add and delete items dynamically. Furthermore, the elements are not kept in a continuous state. As a result, there is no need to expand the size. Also, the doubly linked list data structure is used to implement the LinkedList internally. 

In addition, a normal linked list and a doubly Linkedlist Java has the biggest difference is that the latter has an extra pointer, usually referred to as the previous pointer, in addition to the next pointer and data found in the singly linked list.

Linkedlist java

Exploring Constructors in the LinkedList Java

Firstly, you must create a LinkedList object if you want to generate a Linkedlist Java. Besides, the LinkedList class contains a number of constructors that allow the list to be built. Then, which are they? So, let’s take a look at them below:

#1. LinkedList(): In fact, this constructor is used to generate a linked list that is empty. So, if we want to make an empty LinkedList with the name ll, we can do so as follows:

LinkedList ll = new LinkedList(); 

#2. LinkedList(Collection C): Firstly, if you wish to generate an ordered list that contains all of the elements of a given collection, LinkedList (Collection C) is the ideal choice. Then, it will be returned by the iterator. Besides, if we want to make a linkedlist with the name ll, we can do so as follows:

LinkedList ll = new LinkedList(C); 

Methods

  • Firstly, add(int index, E element)
  • Secondly, add(E e)
  • Thirdly, addAll(int index, Collection<E> c)
  • Forthly, addAll(Collection<E> c)
  • addFirst(E e)
  • Nextly, addLast(E e)
  • clear()
  • clone()
  • contains(Object o)
  • descendingIterator()
  • element()
  • get(int index)
  • getFirst()
  • Nextly, getLast()
  • indexOf(Object o)
  • lastIndexOf(Object o)
  • listIterator(int index)
  • offer(E e)
  • offerFirst(E e)
  • offerLast(E e)
  • peek()
  • peekFirst()
  • peekLast()
  • poll()
  • pollFirst()
  • pollLast()
  • pop()
  • push(E e)
  • remove()
  • remove(int index)
  • remove(Object o)
  • removeFirst()
  • removeFirstOccurrence(Object o)
  • removeLast()
  • removeLastOccurrence(Object o)
  • set(int index, E element)
  • size()
  • spliterator()
  • toArray()
  • toArray(T[] a)
  • Finally, toString()

In conclusion

In short, the article above is an overview about Linkedlist Java. Through it, we delivered you all helpful information about its definition, implemetation and so on.

All in all, ArrowHiTech hopes this blog is extremely useful for you and you are able to take a lot of benefits from it. Then, you will master Java as soon as possible. During the process of working with Java, if you have any struggles or any questions, free to CONTACT US. At ArrowHiTech, our professionals have expertise in building business-specific Web applicationsMobile App that meet your high expectations and quality standards

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