Stack Implementation using Linked List in Java

Stack Implementation using Linked List

Last Updated: 19 January, 2025 🕓 5 Mins

In this tutorial page, we are going to learn about how to implement a stack data structure using a linked list in Java.

By the end of this tutorial, you will have a clear understanding of both stack operations and how to effectively utilize linked lists in Java to create a dynamic stack implementation. This knowledge will help you to manage data more efficiently.

Stack data structure implementation

There are two ways to implement a stack data structure:

Using Array

Using Linked List

Let's see the Stack implementation using Linked List in Java.

Stack implementation using Linked List in Java

In a linked list-based stack implementation, the push operation is implemented by creating a new node with the new element and setting the next pointer of the current top node to the new node. The pop operation is implemented by setting the next pointer of the current top node to the next node and returning the value of the current top node.

  public class StackUsingLinkedList {
    
    private StackNode root;
  
    static class StackNode {
      int data; 				// Store node value
      StackNode next; 		    // Store address to the next node
  
      StackNode(int data) {
        this.data = data;
      }
    }
  
    // Adding new item into the stack
    public void push(int data) {
      StackNode newNode = new StackNode(data);
      // checks stack is empty
      if (root == null) {
        root = newNode;
      } else {
        StackNode temp = root;
        root = newNode;
        newNode.next = temp;
      }
      System.out.println(data + " pushed to the stack");
    }
  
    // Removing an item from the stack
    public void pop() {
      int popped = Integer.MIN_VALUE;
      // checks stack is empty
      if (root == null) {
        System.out.println("Stack is Empty");
      } else {
        popped = root.data;
        root = root.next;
      }
      System.out.println(popped + " popped from the stack");
    }
  
    // Returns top element of the stack.
    public void peek() {
      // check stack is empty
      if (root == null) {
        System.out.println("Stack is empty");
      } else {
        System.out.println("Top element of stack: " + root.data);
      }
    }
  
    // Print linked list items
    public void printLinkedList() {
      // Traverse the linked list until reaching the end
      while (root != null) {
        System.out.print(root.data + " ");
        // Move to the next node
        root = root.next;
      }
    }
  
    // Driver code
    public static void main(String[] args) {
      StackUsingLinkedList stack = new StackUsingLinkedList();
  
      stack.push(10); // Insert item
      stack.push(20); // Insert item
      stack.push(30); // Insert item
  
      stack.pop(); // Remove item
  
      stack.peek(); // Return top item of the stack
  
      stack.push(50); // Insert item
      stack.push(60); // Insert item
  
      stack.pop(); // Remove item
  
      stack.printLinkedList(); // Print linked list items
    }
  }

10 pushed to the stack
20 pushed to the stack
30 pushed to the stack
30 popped from the stack
Top element of stack: 20
50 pushed to the stack
60 pushed to the stack
60 popped from the stack
50 20 10