100 Full Stack Interview Questions and Answers

Answer:

Full Stack development involves developing both the front end and back end of the web application/website at the same time. This process includes three layers:

• Presentation layer (frontend part responsible for user experience)
• Business logic layer (backend part refers to the server side of the application)
• Database layer

Answer:

A Full Stack developer should be familiar with:

• Basic languages – Must be proficient in basic languages like HTML, CSS, and SQL.
• Front-end frameworks – BootStrap, AngularJS, VueJS, ReactJS, JavaScript, TypeScript, Python, Ruby, PHP.
• Back-end frameworks – Express, Django, NodeJS, Ruby on Rails.
• Databases – MySQL, SQLite, Postgres, MongoDB, Cassandra, Apache storm, Sphinx.
• Additional skills recommended – Git, Machine Learning, SSH, Linux Command, Data Structures, Character encoding.

Answer:

As the name suggests, Pair Programming is where two programmers share a single workstation. Formally, one programmer at the keyboard called the “driver” writes the code. The other programmer is the “navigator” who views each line of the code written, spell check, and proofread it. Also, programmers will swap their roles every few minutes and vice-versa.

Answer:

Cross-origin resource sharing (CORS) is a process that utilizes additional HTTP headers to tell browsers to provide a web application running at one origin. CORS accesses various web resources on different domains. Web scripts can be integrated using CORS when it requests a resource that has an external origin (protocol. Domain, or port) from its own.

Answer:

Inversion of Control (IoC) is a broad term used by software developers for defining a pattern that is used for decoupling components and layers in the system. It is mostly used in the context of object-oriented programming. Control of objects or portions of a program is transferred to a framework or container with the help of Inversion of Control. It can be achieved using various mechanisms such as service locator pattern, strategy design pattern, factory pattern, and dependency injection.

Answer:

If the data within the API is publicly accessible, then it’s not possible to prevent data scraping completely. However, there is an effective solution that will deter most people/bots: rate-limiting (throttling).

Throttling will prevent a specific device from making a defined number of requests within a defined time. Upon exceeding the specified number of requests, 429 Too Many Attempts  HTTP error should be thrown.

Other possible solutions to prevent a bot from scrapping are:

• Blocking requests based on the user agent string.
• Generating temporary “session” access tokens for visitors at the front end.

Answer:

REST stands for representational state transfer. A RESTful API (also known as REST API) is an architectural style for an application programming interface (API or web API) that uses HTTP requests to obtain and manage information. That data can be used to POST, GET, DELETE, and OUT data types, which refers to reading, deleting, creating, and operations concerning services.

Answer:

A callback in JavaScript is a function passed as an argument into another function, that is then requested inside the outer function to make some kind of action or routine. JavaScript callback functions can be used synchronously and asynchronously. APIs of the node are written in such a way that they all support callbacks.

Answer:

This is typically a difficult question to answer, but a good developer will be able to go through this with ease. The core difference is GraphQL doesn’t deal with dedicated resources. The description of a particular resource is not coupled to the way you retrieve it. Everything referred to as a graph is connected and can be queried to application needs.

Answer:

Long polling is defined as a web application development technique used to push information/data from servers to clients as quickly as possible. When a request is made from the client to the server, long-polling maintains the connection between the two. This connection is maintained until the information is ready to be sent from the server to the client.  Once a server receives a request from a client, the connection does not close immediately; the connection is only closed once the server has sent the data back to the client or when a timeout threshold has been reached (connection timeout).

Answer:

In Java, a connection leak is a situation when the developer forgets to close the JDBC connection, it is known as connection leak. The most common type of Connection Leak experienced in Java development, is when using a Connection Pool (such as DBCP). We can fix it by closing the connection and giving special attention to the error handling code.

Answer:

Spring MVC Framework provides the following ways to handle exceptions:

• Controller-Based: We can define the exception handler method in our controller class.
• Global Exception Handler: Exception handling is a cross-cutting concern that Spring
• HandlerExceptionResolver: Any Spring Bean declared in the DispatcherServlet’s application context that implements HandlerExceptionResolver will be used to intercept and process any exception raised in the MVC system and not handled by a Controller.

Answer:

Multithreading is the process of improving the performance of the CPU. It is typically the ability of a program, where multiple users can manage it simultaneously. Multithreading is when the operating system duly supports the execution of multiple processes.

Continuous integration is the execution of specially designed codes that are automated for testing. It simply helps the developers to implement the codes during the production time. Continuous integration aids in detecting errors faster and resolving them easily. That is why web developers prefer to integrate codes several times a day.

Answer:

The best ways to enhance scalability and efficiency are:

• Reducing DNS lookup
• Avoiding duplicate codes
• Avoiding URL redirects
• Leveraging browser caching
• Avoiding unnecessary images
• Avoiding inline JavaScript and CSS
• Deferring parsing of JavaScript
• Placing all assets on a cookie-free domain, preferably using a CDN.
• Using srcset attribute for responsive images

Answer:

A design pattern is a reproducible or reusable solution for frequent problems in software design. Such patterns show the relationships and interactions between classes and objects. There are three main types of design patterns:

• Creational: Related to class instantiation and object creation. These are further categorized into class-creational patterns and object-creational patterns.
• Structural: Related to the organization of different classes and objects to provide new and more extensive functionality.
• Behavioral: Concerned with identifying common communication patterns between objects.

Answer:

In object oriented programming, when two objects share some properties but don’t necessarily share methods, we call it bridge pattern. For example, if we want to create a new class that inherits from another class, we would use bridge pattern.

Answer:

Selectors in CSS refer to ways which are used to locate a particular HTML element in the CSS file to style. In CSS, there are five types of selectors, which are as follows:

• Simple Selectors– In simple selectors, we select elements based on their id, class, and name.
• Combinator Selectors– In this, elements are selected based on the relationship between them.
• Pseudo-Class Selectors– This selects elements based on their state.
• Pseudo-Elements Selectors– This type of selector selects a part of the HTML elements and styles it.
• Attribute Selectors– Attribute Selectors are used to styling an HTML element based on its attribute or its attribute value.

Answer:

Replication in MongoDB happens to be a practice of syncing data across several servers. With numerous copies of data on separate database servers, replication offers redundancy and boosts data availability. Replication safeguards a database against the loss of a single server. Users may also recover from hardware failures and service interruptions through replication. Users can assign one copy of the data to disaster recovery, reporting, or backup.

Answer:

NPM (Node Package Manager) is a type of JavaScript software registry over the web that is used by developers to share, download, and borrow various types of packages that are used for installation and dependencies resolving purposes.

Node Package Manager has three different types of components –

• Website– The website is used for package discovery and profile management.
• Command Line Interface– CLI is a type of terminal used to run NPM in the developer’s system.
• Registry– A registry is a type of database which have JavaScript files and associated metadata.

In Node.Js Node Package Manager is used to set up the Node.Js development environment in the user’s system, download the needed packages, and resolve dependencies issues.

Answer:

The conversion of a smaller numeric type to a larger numeric type is known as numeric promotion. In this type, byte, char, and short values are converted to int values. The int values are converted to long values, if necessary. The long and float values are converted to double values, as needed.