Virtusa Software Services Senior Software Engineer Interview Questions and Answers

Services in Android are components that run in the background to perform long-running operations.

• Services can be used to play music in the background while the user interacts with other apps.

• They can also be used to download files from the internet even when the app is not in the foreground.

• Services can run indefinitely or be scheduled to run at specific times.

• They can communicate with other components using broadcasts

Dependency Injection in Spring is a design pattern where objects are passed their dependencies rather than creating them internally.

• In Spring, dependencies are injected into a class through constructor injection, setter injection, or field injection.

• This helps in achieving loose coupling between classes and makes the code more testable and maintainable.

• Example: @Autowired annotation in Spring is used for dependency inj

I have over 8 years of experience in IT, specializing in software development and project management.

• Developed web applications using Java, Spring, and AngularJS

• Led a team of developers in implementing a new CRM system for a large client

• Managed multiple projects simultaneously, ensuring on-time delivery and client satisfaction

SOLID is a set of five design principles for writing maintainable and scalable object-oriented software.

• Single Responsibility Principle (SRP) - A class should have only one reason to change.

• Open/Closed Principle (OCP) - Software entities should be open for extension but closed for modification.

• Liskov Substitution Principle (LSP) - Objects of a superclass should be replaceable with objects of its subclasses without affe...read more

OOPs (Object-Oriented Programming) is a programming paradigm based on the concept of objects, which can contain data and code.

• Encapsulation: Bundling data and methods that operate on the data into a single unit (object)

• Inheritance: Ability for a class to inherit properties and behavior from another class

• Polymorphism: Ability for objects of different classes to respond to the same message in different ways

• Abstraction: H...read more

The .Net framework is a software development platform developed by Microsoft, providing a wide range of tools and libraries for building various types of applications.

• Common Language Runtime (CLR) - manages memory, security, and execution of code

• Base Class Library (BCL) - provides a set of reusable classes for common programming tasks

• ASP.NET - framework for building web applications

• Windows Presentation Foundation (WPF)...read more

let, var, and const are all used to declare variables in JavaScript, but they have different scoping rules and behaviors.

• let and const were introduced in ES6, while var has been around since the beginning of JavaScript.

• let and const are block-scoped, while var is function-scoped.

• Variables declared with const cannot be reassigned, while let and var can be.

• const variables must be initialized when they are declared, while...read more

Scopes in JavaScript determine the accessibility of variables and functions.

• Global scope: variables and functions declared outside any function are accessible globally

• Local scope: variables and functions declared inside a function are only accessible within that function

• Block scope: variables declared with let and const are only accessible within the block they are declared in

• Function scope: variables declared with var...read more

Callback hell is a situation where nested callbacks make code unreadable. Promises are a solution to this problem.

• Callback hell occurs when there are too many nested callbacks in asynchronous code

• It makes the code difficult to read and maintain

• Promises are a way to handle asynchronous operations without nested callbacks

• Promises can be used to chain multiple asynchronous operations together

• Promises have a resolve and re...read more

Express.js is a popular Node.js web framework used for building web applications. Body-parser is a middleware used to parse incoming request bodies.

• Express.js is a minimal and flexible Node.js web application framework that provides a robust set of features for web and mobile applications.

• It provides a way to handle HTTP requests and responses, routing, middleware, and more.

• Body-parser is a middleware used to parse inc...read more

Arrow functions are a concise way to write functions in JavaScript.

• They have a shorter syntax than traditional function expressions.

• They do not have their own 'this' keyword.

• They are not suitable for methods, constructors, or prototype methods.

• Example: const add = (a, b) => a + b;

• Example: const square = x => x * x;

Node.js is a server-side JavaScript runtime environment.

• Node.js is built on top of the V8 JavaScript engine from Google Chrome.

• It allows developers to write server-side code in JavaScript.

• Node.js has a non-blocking I/O model, making it efficient for handling large amounts of data.

• Node.js has a vast library of modules available through npm (Node Package Manager).

Passport.js is an authentication middleware for Node.js.

• Passport.js provides a simple way to authenticate users with various authentication strategies such as local, OAuth, OpenID, etc.

• It is highly customizable and can be integrated with any Node.js web application framework.

• Passport.js maintains user sessions and provides a consistent API for authentication across different strategies.

• Example: Using Passport.js with E...read more

Node is a runtime environment for executing JavaScript code, while Express is a web application framework built on top of Node.

• Node provides the platform for running JavaScript code outside of a web browser

• Express is a lightweight framework that simplifies building web applications on top of Node

• Express provides features like routing, middleware, and templating that make it easier to build web applications

• Node and Expr...read more

Node.js is single-threaded to optimize performance and simplify programming.

• Node.js uses an event-driven, non-blocking I/O model.

• This allows for efficient handling of multiple requests without creating new threads.

• Node.js also uses a single event loop to manage all I/O operations.

• This simplifies programming by eliminating the need for complex thread synchronization.

• However, Node.js can still take advantage of multi-cor

Function hoisting is a JavaScript behavior where function declarations are moved to the top of their scope.

• Function declarations are moved to the top of their scope during the compilation phase.

• Function expressions are not hoisted.

• Hoisting can lead to unexpected behavior and bugs if not understood properly.

Event loop is a mechanism that allows JavaScript to perform non-blocking I/O operations.

• Event loop is a loop that constantly checks the message queue and executes the next message if there is any.

• Phases are the different stages of the event loop, such as timers, I/O callbacks, idle, and poll.

• Event loop is crucial for Node.js to handle multiple requests simultaneously without blocking the main thread.

• Example: setTimeout...read more