JAVA LinkedList
What is Java Linked List?
Java LinkedList is a class in Java’s Collection Framework that provides a linked list implementation of the List interface. The LinkedList class stores its elements in nodes, where each node contains both the element and a reference to the next node in the list.
This means that each element in the list is not stored in contiguous memory, unlike the ArrayList. Instead, the elements are connected through references. To Understand the Java LinkedList, Read the Java complete article.
Creating a Java LinkedList
- To create a LinkedList in Java, you need to do the following steps:
- Import the LinkedList class from the java.util package.
- Create an instance of the LinkedList class using the new keyword.
- Add elements to the LinkedList using the add() method.
Example 1:Java program for Creation Of Java LinkedList.
//Creation of Java Linked List
import java.util.LinkedList;
public class Main
{
public static void main (String[]args)
{
LinkedList < String > names = new LinkedList <> ();
// Adding elements to the list
names.add ("Ashish");
names.add ("anjali");
names.add ("vibudh");
// Printing the list to the console
System.out.println (names);
}
}
Output
[Ashish, anjali, vibudh]
Explanation:
we created a LinkedList of strings and added three elements to it.
We then accessed the first element using the get() method and removed the second element using the remove() method.
we iterated over the remaining elements using a for-each loop and printed them to the console.
Methods of LinkedHashSet
The Java LinkedList class provides a wide range of methods for working with linked lists. Here is a list of some of the most commonly used methods:
add(E element): Adds the specified element to the end of the list.
remove(): Removes and returns the first element from the list.
clear(): Removes all elements from the list.
get(int index): Returns the element at the specified position in the list.
These are just some of the methods available in the LinkedList class.
There are many more methods available for manipulating and accessing linked lists in Java.
| Method | Description |
|---|---|
| contains(Object o) | Returns true if the list contains the specified element. |
| indexOf(Object o) | Returns the index of the first occurrence of the specified element in the list, or -1 if the element is not found. |
| lastIndexOf(Object o) | Returns the index of the last occurrence of the specified element in the list, or -1 if the element is not found. |
| iterator() | Returns an iterator over the elements in the list |
| listIterator() | Returns a list iterator over the elements in the list. |
Let’s look at the Java LinkedList to perform certain operations.
Example 1:Java program to Insert Elements to LinkedHashSet.
Run
//AddElementsToLinkedList
import java.util.LinkedList;
public class Main
{
public static void main (String[]args)
{
LinkedList < String > linkedList = new LinkedList <> ();
// add elements to the linked list
linkedList.add ("Bat");
linkedList.add ("Ball");
linkedList.add ("wicket");
// print the contents of the linked list
System.out.println ("LinkedList: " + linkedList);
}
}
Output
LinkedList: [Bat, Ball, wicket]
Explanation:
In this program, we first create a new LinkedList object using the LinkedList class. We then use the add() method to add three elements to the linked list: "Bat", "Ball", and "wicket". Finally, we print the contents of the linked list using the System.out.println() method.
Example 2 : Java program to Access LinkedList Elements
Run
//AccessLinkedListElements
import java.util.LinkedList;
public class Main {
public static void main(String[] args) {
LinkedList linkedList = new LinkedList<>();
// add elements to the linked list
linkedList.add("Nokia");
linkedList.add("Samsung");
linkedList.add("Motorola");
// access the first element in the linked list
String firstElement = linkedList.get(0);
System.out.println("First Element: " + firstElement);
// access the second element in the linked list
String secondElement = linkedList.get(1);
System.out.println("Second Element: " + secondElement);
// access the third element in the linked list
String thirdElement = linkedList.get(2);
System.out.println("Third Element: " + thirdElement);
}
}
Output
First Element: Nokia Second Element: Samsung Third Element: Motorola
Explanation:
We then use the add() method to add three elements to the linked list: "Nokia", "Samsung", and "Motorola".
Next, we use the get() method to access the first, second, and third elements in the linked list. We store each element in a separate variable and then print the variables to the console using the System.out.println() method.
Example 3 : Java program to Remove Elements from LinkedList
Run
import java.util.LinkedList;
//RemoveFromLinkedList
public class Main {
public static void main(String[] args) {
LinkedList linkedList = new LinkedList<>();
// add elements to the linked list
linkedList.add("Boat");
linkedList.add("Bike");
linkedList.add("Airplane");
// print the contents of the linked list before removing an element
System.out.println("LinkedList: " + linkedList);
// remove the second element from the linked list
linkedList.remove(1);
// print the contents of the linked list after removing an element
System.out.println("LinkedList after removing second element: " + linkedList);
}
}
Output
LinkedList: [Boat, Bike, Airplane] LinkedList after removing second element: [Boat, Airplane]
Explanation:
we use the remove() method to remove the second element (index 1) from the linked list. we print the contents of the linked list again to verify that the element was removed.
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