Accenture Fullstack Interview Questions and Answers

1. What are the advantages of using React?

Advantages of React JS

Component-based architecture,
Virtual DOM for efficient updates,
Unidirectional data flow,
Strong community and ecosystem.

2. How do you manage state in a React application?

In a React application, State can be managed by:

React’s built-in useState,
Context API,
useReducer hooks,
state management libraries like Redux.

3. What is the purpose of useEffect in React?

useEffect is used for performing side effects in function components, such as: Data fetching, subscriptions and manually changing the DOM.

4. What is the difference between a class component and a functional component in React?

Class components use ES6 classes and lifecycle methods. Functional components are simpler and use hooks for state and lifecycle management.

5. Explain the concept of virtual DOM in React.

The virtual DOM is an in-memory representation of the real DOM elements generated by React components. It updates efficiently by comparing with previous states and applying only necessary changes.

6. How do you implement routing in a React application?

Using React Router:

import { BrowserRouter as Router, Route, Switch } from ‘react-router-dom’; <Router> <Switch> <Route path="/" exact component={Home} /> <Route path="/about" component={About} /> </Switch> </Router>

7. Explain the concept of RESTful APIs.

RESTful APIs follow REST principles, using standard HTTP methods (GET, POST, PUT, DELETE) for CRUD operations and resource-based URIs.

8. What is middleware in Express.js?

Middleware functions are functions that have access to the request and response objects. It can modify them or end the request-response cycle.

9. How do you handle authentication in a Node.js application?

To handle authentication in a Node.js application, use libraries like Passport.js or JWT for token-based authentication.

10. What is the purpose of async/await in JavaScript?

async/await syntax allows writing asynchronous code in a synchronous manner. It improves readability and maintainability.

11. Explain the difference between process.nextTick() and setImmediate().

process.nextTick() schedules a callback to be invoked in the next iteration of the event loop. setImmediate() schedules a callback to be executed after I/O events.

12. Explain the difference between SQL and NoSQL databases.

SQL databases are relational, use structured query language, and have a predefined schema. NoSQL databases are non-relational, schema-less, and can handle unstructured data.

13. What is the purpose of module.exports in Node.js?

module.exports is used to export modules in Node.js. It allows the modules to be used when required.

14. How do you normalize a database?

By organizing the database into tables and columns. It reduces redundancy and improves data integrity, typically through normal forms (1NF, 2NF, 3NF, etc.).

15. What is an ORM and why is it used?

Object-Relational Mapping (ORM) is a technique for converting data between incompatible type systems using object-oriented programming languages. It simplifies database interactions.

16. What is database sharding?

Sharding is a method of distributing data across multiple databases or servers. It improves scalability and performance.

17. How do you backup and restore a database?

To create backups and restore databases, use database-specific tools and commands (e.g., mysqldump for MySQL, pg_dump for PostgreSQL).

18. Explain the concept of closures in JavaScript.

A closure is a function that retains access to its lexical scope when the function is executed outside that scope.

19. What are design patterns? Name a few commonly used ones.

Design patterns are typical solutions to common problems in software design. Examples: Singleton, Observer, Factory, and Strategy patterns.

20. What is the purpose of version control?

Version control systems (Git) help to manage changes to source code over time. It allows multiple developers to collaborate and track revisions.

21. How do you handle asynchronous operations in JavaScript?

Handle asynchronous operations in JavaScript using callbacks, Promises, and async/await.

22. What is event delegation in JavaScript?

Event delegation is a technique of using a single event listener to manage events for multiple elements.

23. Explain the concept of microservices.

Microservices architecture structures an application as a collection of loosely coupled applications. It has independently deployable services that communicate over a network.

24. What are WebSockets and how do they differ from HTTP?

WebSockets provide full-duplex communication channels over a single TCP connection, unlike HTTP which is a request-response protocol.

25. What is server-side rendering (SSR) and its benefits?

SSR renders web pages on the server instead of the client. It improves initial load time and SEO.

26. How would you implement a thread-safe singleton pattern in Java?

public class Singleton { private static volatile Singleton instance; private Singleton() { // private constructor to prevent instantiation } public static Singleton getInstance() { if (instance == null) { synchronized (Singleton.class) { if (instance == null) { instance = new Singleton(); } } } return instance; } }

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Accenture Fullstack Interview Questions and Answers