What is Stack in Java? [2023]

If you’re new to Java programming, you may have come across the term “stack” and wondered what it means. In this article, we’ll dive into the world of stacks in Java and explore their purpose, implementation, and usage. So, let’s get started!

Table of Contents

Quick Answer

A stack in Java is a data structure that follows the Last-in-First-out (LIFO) principle. It is implemented using the Java Stack class, which is part of the Collection Framework. The Stack class extends the Vector class and provides methods for adding, removing, and accessing elements in a stack-like manner.

Quick Tips and Facts:

  • A stack is a collection of elements where the last element added is the first one to be removed.
  • The Java Stack class is based on the Vector class and implements the List interface.
  • The Stack class provides methods such as push(), pop(), peek(), empty(), and search().

What is Stack Data Structure

A stack is a fundamental data structure in computer science that follows the Last-in-First-out (LIFO) principle. It can be visualized as a stack of objects, where the last object placed on top is the first one to be removed. Think of a stack of books or a deck of cards.

In Java, the stack data structure is implemented using the Stack class, which is part of the Collection Framework. The Stack class extends the Vector class and provides additional methods for stack-specific operations.

Java Stack Class of Collection Framework

The Java Stack class is a subclass of the Vector class and implements the List interface. It inherits all the methods from the Vector class and adds stack-specific methods. Here are some key points about the Java Stack class:

  • The Stack class is defined in the java.util package.
  • It extends the Vector class, which means it inherits all the methods from the Vector class.
  • The Stack class implements the List interface, making it a collection that maintains the order of its elements.
  • The Stack class is synchronized, which means it is thread-safe for use in multi-threaded environments.

Java Stack Methods

The Java Stack class provides several methods for manipulating and accessing elements in a stack-like manner. Here are some commonly used methods:

  • push(element): Adds an element to the top of the stack.
  • pop(): Removes and returns the element at the top of the stack.
  • peek(): Returns the element at the top of the stack without removing it.
  • empty(): Checks if the stack is empty.
  • search(element): Searches for an element in the stack and returns its position.

Stack Code Example

Let’s take a look at a code example to understand how the Java Stack class is used:

import java.util.Stack;

public class StackExample {
    public static void main(String[] args) {
        Stack<String> stack = new Stack<>();

        // Pushing elements to the stack
        stack.push("Java");
        stack.push("is");
        stack.push("awesome");

        // Popping elements from the stack
        String element = stack.pop();
        System.out.println(element); // Output: awesome

        // Peeking at the top element
        String topElement = stack.peek();
        System.out.println(topElement); // Output: is

        // Checking if the stack is empty
        boolean isEmpty = stack.empty();
        System.out.println(isEmpty); // Output: false

        // Searching for an element in the stack
        int position = stack.search("Java");
        System.out.println(position); // Output: 2
    }
}

In this example, we create a stack using the Stack class and perform various operations such as pushing elements, popping elements, peeking at the top element, checking if the stack is empty, and searching for an element in the stack.

What about Your Own Stack Implementation?

While the Java Stack class provides a convenient way to work with stacks, you can also implement your own stack if needed. Implementing your own stack allows you to have more control over its behavior and customize it according to your specific requirements.

If you decide to implement your own stack, you can use an array or a linked list as the underlying data structure. Both approaches have their pros and cons, so choose the one that best suits your needs.

Should We Use Java Stack?

The decision to use the Java Stack class depends on your specific use case. Here are some factors to consider:

Pros:

  • Convenient methods: The Java Stack class provides methods for common stack operations, making it easy to work with stacks.
  • Thread-safe: The Stack class is synchronized, making it safe to use in multi-threaded environments.

Cons:

  • Performance: The Stack class is based on the Vector class, which is synchronized and has some performance overhead. If performance is a concern, consider using other data structures like ArrayList or LinkedList.

In modern Java programming, the ArrayList class is usually preferred over the Stack class due to its better performance and lack of synchronization. However, if you specifically need a stack data structure, the Java Stack class can still be a viable option.

FAQ

Made with Canon 5d Mark III and loved analog lens, Leica APO Macro Elmarit-R 2.8 / 100mm (Year: 1993)

What is a stack in Java programming?

A stack in Java programming is a data structure that follows the Last-in-First-out (LIFO) principle. It is implemented using the Java Stack class, which provides methods for adding, removing, and accessing elements in a stack-like manner.

Read more about “Is Stack a Class or Interface? …”

What is stack and its types?

A stack is a data structure that follows the Last-in-First-out (LIFO) principle. There are two main types of stacks: fixed-size stacks and dynamic stacks. Fixed-size stacks have a predetermined size and cannot grow or shrink, while dynamic stacks can resize themselves as needed.

Read more about “Stack Interface: A Comprehensive Guide …”

Why would you use a stack in Java?

You would use a stack in Java when you need to store and retrieve elements in a Last-in-First-out (LIFO) order. Stacks are commonly used in algorithms, recursion, expression evaluation, and undo/redo operations.

What is the purpose of stack?

The purpose of a stack is to provide a data structure that allows efficient insertion and removal of elements in a Last-in-First-out (LIFO) order. Stacks are used in various applications, including expression evaluation, function call management, and backtracking algorithms.

Read more about “Ultimate Best Web and Native App Tech Stack”

Conclusion

In this article, we explored the concept of stacks in Java and learned about the Java Stack class. We discussed its implementation, methods, and usage. While the Java Stack class provides convenient methods for working with stacks, it’s important to consider your specific use case and performance requirements. Whether you choose to use the Java Stack class or implement your own stack, understanding the fundamentals of stacks will help you in various programming scenarios.

Jacob
Jacob

Jacob is a software engineer with over 2 decades of experience in the field. His experience ranges from working in fortune 500 retailers, to software startups as diverse as the the medical or gaming industries. He has full stack experience and has even developed a number of successful mobile apps and games.

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