If you want to practice data structure and algorithm programs, you can go through data structure and algorithm interview questions.This is one of popular interview question.

## Java Linked List Interview Programs:

- How to detect a loop in linked list in java
Find start node of loop in linkedlist
How to find middle element of linked list in java
How to find nth element from end of linked list
How to reverse a linked list in java
Add two numbers represented by linked list in java

- Iterative
- Recursive

#### Iterative:

Logic for this would be:- Have three nodes i.e previousNode,currentNode and nextNode
- When currentNode is starting node, then previousNode will be null
- Assign currentNode.next to previousNode to reverse the link.
- In each iteration move currentNode and previousNode by 1 node.

public static Node reverseLinkedList(Node currentNode) { // For first node, previousNode will be null Node previousNode=null; Node nextNode; while(currentNode!=null) { nextNode=currentNode.next; // reversing the link currentNode.next=previousNode; // moving currentNode and previousNode by 1 node previousNode=currentNode; currentNode=nextNode; } return previousNode; }Java program for this will be :

package org.arpit.java2blog; public class LinkedList{ private Node head; private static class Node { private int value; private Node next; Node(int value) { this.value = value; } } public void addToTheLast(Node node) { if (head == null) { head = node; } else { Node temp = head; while (temp.next != null) temp = temp.next; temp.next = node; } } public void printList(Node head) { Node temp = head; while (temp != null) { System.out.format("%d ", temp.value); temp = temp.next; } System.out.println(); } // Reverse linkedlist using this function public static Node reverseLinkedList(Node currentNode) { // For first node, previousNode will be null Node previousNode=null; Node nextNode; while(currentNode!=null) { nextNode=currentNode.next; // reversing the link currentNode.next=previousNode; // moving currentNode and previousNode by 1 node previousNode=currentNode; currentNode=nextNode; } return previousNode; } public static void main(String[] args) { LinkedList list = new LinkedList(); // Creating a linked list Node head=new Node(5); list.addToTheLast(head); list.addToTheLast(new Node(6)); list.addToTheLast(new Node(7)); list.addToTheLast(new Node(1)); list.addToTheLast(new Node(2)); list.printList(head); //Reversing LinkedList Node reverseHead=reverseLinkedList(head); System.out.println("After reversing"); list.printList(reverseHead); } }Run above program, you will get following output:

5 6 7 1 2 After reversing 2 1 7 6 5

#### Recursive:

**Base case:**Base case for this would be either node is null or node.next is null

For recursive solution, replace reverseLinkedList of above program to below function

public static Node reverseLinkedList(Node node) { if (node == null || node.next == null) { return node; } Node remaining = reverseLinkedList(node.next); node.next.next = node; node.next = null; return remaining; }Output of this program will be same as above program.

Now lets understand logic for above recursive program.

5->6->7->1->2

Above function will terminate when last node(2) 's next will be null.so while returning when you reach at node with value 1,If you closely observe

**node.next.next=node**is actually setting 2->1(i.e. reversing the link between node with value 1 and 2) and

**node.next=null**is removing link 1->2. So in each iteration, you are reversing link between two nodes.

Below diagram will make it clear

Please go through java interview programs for more such programs.