Ace Your Next Interview With These Dot Net Core Interview Questions

Dot NET Core is a free and open-source framework by Microsoft for building apps. It works on Windows, Linux, and macOS, making it great for cross-platform development. It is fast, lightweight, and modular, so developers can use only the parts they need. Dot NET Core supports web apps, microservices, cloud applications, and more. It also works well with Docker and Kubernetes for modern deployments. Unlike the old Dot NET Framework, it does not depend on Windows. Because of its high performance and flexibility, many Indian developers and companies use Dot NET Core for modern software projects.

Characteristics of Dot NET Core:

Dot NET Core comes with several powerful characteristics that make it a preferred choice for modern application development. Because of it versatility it allows developers to build high-performance applications for web, cloud, and microservices. Here are some of the characteristics that can be part of net core interview questions for freshers:

• Cross-platform: Many operating systems like Linux, macOS, and Windows support Dot Net Core.
• Open-source and Free: You can obtain the Dot Net Core source code project from Github. It is licensed and free under the Apache and MIT licenses.
• Sharable: Dot Net Core uses a single constant API model that is inscribed in Dot NET Standard. It is standard for all the Dot net applications. The same API or library can be utilised on multiple platforms with dissimilar languages.
• Friendly: The Dot Net Core is compatible with Dot Net Framework, Xamarin, and Mono through Dot NET Standard. Also, it supports working with various libraries and Web frameworks like JavaScript, React, and Angular.‍
• Fast: Dot Net Core 3.0 is quicker as compared to the Dot Net Core 2.2, Dot Net Framework, and earlier versions. Also, it is much faster compared to other server-side frameworks such as Java Servlet and Node.js.

Differentiate Dot NET Core vs Dot NET framework

When choosing between Dot NET Core and Dot NET Framework, developers often get confused about which one suits their needs. Both have their strengths, but they are designed for different purposes. Understanding their differences helps in selecting the right technology for your project and when dealing with net core questions freshers should be aware of these:

What is ASP Dot NET Core?

ASP Dot NET Core is an open-source, cross-platform framework developed by Microsoft for building modern web applications, APIs, and cloud-based services. It is a re-engineered version of ASP Dot NET, designed for high performance, flexibility, and scalability. ASP Dot NET Core supports Windows, macOS, and Linux, making it suitable for cross-platform development. It integrates seamlessly with Docker, Kubernetes, and cloud services, making it ideal for microservices architecture.

Characteristics of ASP Dot NET Core

1. Cross-Platform Compatibility

1. Runs on Windows, macOS, and Linux.
2. Allows developers to build and deploy applications across different environments.

2. High Performance & Lightweight

1. Uses the Kestrel web server, which is faster than IIS.
2. Designed with a modular architecture, allowing developers to include only necessary components.

3. Modern Development Approach

1. Supports MVC (Model-View-Controller) architecture and Razor Pages.
2. Uses Blazor for building interactive web UIs with C# instead of JavaScript.

4. Built-in Dependency Injection

1. Provides a built-in dependency injection (DI) container, making it easy to manage dependencies and improve code maintainability.

5. Cloud & Microservices Ready

1. Easily integrates with Docker, Kubernetes, and Azure.
2. Ideal for developing microservices-based applications.

6. Secure & Open-Source

1. Backed by Microsoft and a strong developer community.
2. Supports authentication and authorisation using Identity Server, OAuth, and JWT.

How is ASP Dot NET Different from ASP?

ASP was a basic scripting language, while ASP Dot NET is a fully-featured web development framework with better performance, security, and modern development standards.

Dot NET Core vs ASP Dot NET Core

In short, Dot NET Core is a development framework used to build various types of applications, while ASP Dot NET Core is a specific web framework within Dot NET Core for developing web applications and APIs.

With the constant demand for cross-platform, scalable, and robust applications, Dot Net core has appeared as the best framework in the software development industry. It doesn’t matter if you want to enter the software development field or an experienced developer; preparing for an interview in Dot Net Core can be daunting. 

The key to success lies in clutching the core concepts and practising Dot Net core interview questions that test your knowledge across different framework aspects. 

Let’s check out some frequently asked Net Core interview questions for experienced and fresher candidates, with their answers:

Q1. What is MVC?

MVC (Model-View-Controller) is a software design pattern used for developing web applications. It separates an application into three interconnected components, making it modular, scalable, and easier to maintain.

MVC is widely used in frameworks like ASP Dot NET Core MVC, Spring MVC (Java), and Ruby on Rails for organising code and improving the separation of concerns.

Three Logical Components of MVC

1. Model (Data Layer)

• Represents the business logic and data of the application.
• Manages database operations, data validation, and processing.
• Sends data to the View for display and receives input from the Controller.

Example:
If an e-commerce app fetches product details, the Model will retrieve product data from the database.

2. View (Presentation Layer)

• Handles the UI (User Interface) of the application.
• Displays data received from the Model and sends user inputs to the Controller.
• Uses HTML, CSS, JavaScript, and templating engines (like Razor in ASP Dot NET).

Example:
A webpage that displays a list of products fetched from the database using the Model.

3. Controller (Logic Layer)

• Acts as an intermediary between the Model and the View.
• Handles user input, processes requests, and updates the Model and View accordingly.
• Defines business logic and directs data flow between components.

Example:
When a user clicks "Add to Cart," the Controller updates the Model and refreshes the View to reflect the cart items.

Q2. How MVC Works Together?

1. User requests a webpage → Sent to Controller
2. Controller processes the request → Calls the Model for data
3. Model fetches data from the database and returns it to the Controller
4. Controller passes the data to the View, which displays it to the user

This structured approach improves code organisation, testability, and maintainability in web applications.

Q3. What is the difference between Razor and MVC Pages in Dot NET Core?

‍MVC stands for Model-view-controller. It gives a more structured approach for bigger applications. Razor Pages are much easier and more suitable for page-based applications. They also reduce the requirements for controllers.

Q4. What is the purpose of the appsettings.json file in Dot NET Core? 

appsettings.json file is used to store configuration settings like application settings, logging configurations, and connection strings. You can access and modify this file without changing the code.  

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Warning"
    }
  },
  "ConnectionStrings": {
    "DefaultConnection":"Server=myServer;Database=myDB;User Id=myUser;Password=myPass;"
  }
}

Q5. What are the perks of Dot NET Core over other frameworks?

• Active Community: Get regular updates and strong support from the developer community and Microsoft.
• Performance: Optimisation and high-speed execution.
• Cross-Platform Compatibility: Can work on macOS, Linux, and Windows.
• Microservices-Friendly: Apt for cloud-based apps.
• Container Support: Works competently with Kubernetes and Docker.

Q6. Explain Dependency Injection in Dot NET Core. 

DI or Dependency Injection is a design pattern which is utilised in Dot Net Core to get IoC (Inversion of Control). It promotes code reusability, testability, and maintainability by injecting dependencies into classes instead of hardcoding them. Dot Net Core gives built-in support for DI through the IServiceCollection interface.

Example:

services.AddScoped<IExampleService, ExampleService>();

Q7. What is the role of Middleware in Dot NET Core?

Middleware in Dot NET Core is software that holds HTTP responses and requests in a pipeline. It gives functionalities like routing, exception handling, logging, and authentication. Middleware modules are performed in the order they are included in the pipeline, and each module can determine whether to pass the request to upcoming middleware or end the pipeline. 

Example:

app.Use(async (context, next) => {
    // Pre-processing logic
    await next.Invoke();
    // Post-processing logic
});

Q8. Tell us the differences between Dot NET Framework and Dot NET Core.

• Performance: Dot Net Core is optimised for scalability and high-performance thanks to its lightweight construction.
• Cross-Platform Support: Dot Net Core is cross-platform. This means that it can function on macOS, Linux, and Windows. Dot Net Framework can run only on Windows.
• Microservices Support: Dot Net Core is suitable for microservices-based architectures. This makes it a perfect option for cloud-based apps. 
• Open-Source: Dot Net Core is community-driven and open-source. This lets developers contribute and improve it endlessly.‍
• Compatibility: Dot Net Core has fewer features than Dot Net Framework, like Windows-specific libraries like Windows Forms and WPF.

Q9. What is Dot NET Core?

Microsoft developed a cross-platform and open-source Dot Net Core framework. Microsoft built this framework to create internet-connected, cloud-based, modern apps. It also gives flexibility, modularity, and high performance across macOS, Linux, and Windows. Unlike the old Dot Net Framework, Dot Net Core is lightweight and competent. This makes it suitable to develop web applications, IoT solutions, and microservices.

Q10. How does Dot Net Core handle cross-platform progress?

Dot Net Core is a cross-platform framework. This implies that it can be operated on Linux, macOS, and Windows. You can achieve this by using a platform-agnostic code or a modular architecture. A good answer will pinpoint that Dot Net Core utilises libraries and platform-independent runtime environments. Candidates should also state the significance of testing apps on all target platforms to ensure compatibility.

Q11. How do you manage configuration settings in a Dot NET Core application?

Configuration settings in Dot Net Core are usually managed via different configuration providers like command-line arguments, environment variables, and JSON files (e.g., appsettings.json). You can access it via the IConfiguration interface. A suitable candidate should discuss installing and accessing these configurations in the Startup class. Also, they should mention the significance of safely handling sensitive information, potentially using services like Azure Key Vault.

Q12. What are 'Tag Helpers' in ASP Dot NET Core, and how do they improve development?

'Tag Helpers' in ASP Dot NET Core enables server-side code to participate in developing and rendering HTML elements in Razor views. They provide an HTML-friendly development experience by binding server-side logic to the HTML markup. You should explain that Tag Helpers enhance the maintainability and readability of code by keeping the markup semantic and clean. Seek examples of common Tag Helpers like input and form helpers and how they simplify HTML generation.

Q13. What is CTS?

The Common Type System (CTS) establishes a standardised set of rules that dictate how data types should be defined and utilised within program code. It serves as a framework for describing all data types used in an application, ensuring consistency across different programming environments.

By adhering to CTS guidelines, developers can create their own classes and functions, fostering interoperability between languages. This allows data types defined in one programming language to be seamlessly accessed and utilised by other programming languages within the Dot NET ecosystem.

Q14. Explain CLS.

CLS or Common Language Specification helps app developers use the inter-language elements that are compatible with specific regulations that come with CLS. CLS also aids in reusing the code among all of the Dot Net compatible languages. 

Q15. Tell us the difference between Int32 and Int.

There is no difference between Int and Int32 in C#. Int32 is a data type offered by the Dot NET framework, while Int is simply codenamed for Int32 in the C# programming language. Both signify a 32-bit signed integer and can be used interchangeably in code.

Q16. What is JIT?

JIT, or Just In Time, is a compiler that translates the intermediate code into the local language throughout the execution.

Q17. Explain the difference between unmanaged and managed code?

The major differences between unmanaged and managed code are listed below - 

‍Q18. What is a Garbage Collector?

A Garbage Collector (GC) is an automatic memory management system in Dot NET that frees up memory by removing unused or unreachable objects. It helps prevent memory leaks and improves application performance by reclaiming memory that is no longer needed.

Key Functions of Garbage Collector:

• Allocates and deallocates memory automatically.
• Identifies and removes objects no longer in use.
• Optimises memory usage and prevents fragmentation.
• Runs in the background to minimise performance impact.

Example:

class Program
{
    static void Main()
    {
        MyClass obj = new MyClass();  // Object created
        obj = null;  // Object no longer needed
        GC.Collect();  // Forces Garbage Collection
    }
}

class MyClass { }

Although GC.Collect() can manually trigger garbage collection, the GC automatically runs when needed, making memory management efficient.

Q19. What is an assembly?

An assembly is basically a file that is automatically created by the compiler. It includes a collection of resources and types that are made to work together and create a logical unit of functionality. In other words, assembly is a logical unit of code or a compiled code. Assemblies are applied in the form of .dll (dynamic link library) or .exe (executable) files.

Q20. Explain the different parts of an Assembly.

An assembly in Dot NET consists of several parts. These parts are packaged together into an EXE or DLL file, which the Dot NET runtime uses to execute the application:

• Manifest: Contains metadata about the assembly, such as version, culture, and referenced assemblies.
• Metadata: Describes types, methods, and other members within the assembly.
• MSIL Code: Platform-independent Intermediate Language (IL) code, which is executed by the CLR.
• Resources: Non-executable data files, like images or configuration settings, embedded within the assembly.

Q21. Explain the different types of assembly.

In Dot NET, assemblies can be categorized into:

1. Private Assemblies: Used by a single application and stored in the application's directory.
2. Shared Assemblies: Can be shared across multiple applications and are typically stored in the Global Assembly Cache (GAC).
3. Global Assemblies: Assemblies stored in the GAC for shared use by multiple applications, allowing version management and reuse.
4. Dynamic Assemblies: Created at runtime using the System.Reflection.Emit namespace, typically for scenarios like code generation.

Q22. What is an EXE and a DLL?

An EXE is an executable file program that you can run directly on your computer. It contains everything needed to run the application, including the code and resources. When you double-click an EXE file, the program starts executing, like a console app or a desktop application.

A DLL is a dynamic link library which isn’t something you can run directly. It's more like a collection of reusable code or resources that other applications can call upon while they're running. Think of it as a toolkit for programs. So, rather than launching it independently, other programs use the functions inside the DLL to perform certain tasks.

Q23. What are Universal Windows Platform(UWP) Apps in Dot NET Core?

UWP Apps are apps designed to run on all Windows 10 devices like PCs, tablets, phones, Xbox, and more. The important thing about UWP is that you write your app once, and it can run across all these devices without any changes.

In Dot NET Core, UWP apps are built using the Universal Windows Platform API. It allows developers to create modern, responsive applications that take full advantage of Windows features. With UWP in Dot NET Core, you can build high-performance apps with a great user experience across all Windows devices.

Q24. What are Delegates in Dot NET Core?

In Dot NET Core, a delegate is like a function pointer or a reference to a method. It enables you to pass methods as arguments and also enables flexible and dynamic method calls. Think of it as a "callback" mechanism when you need to call a method later or pass it around, you can use a delegate. It can point to one or more methods, making it useful for scenarios like event handling and asynchronous programming.

Q25. What is the difference between AddTransient(), AddScoped(), and AddSingleton() in Dot NET Core DI?

• AddTransient() – Creates a new instance every time it's requested.
• AddScoped() – Creates one instance per request.
• AddSingleton() – Creates a single instance for the application's lifetime.

Example in Program.cs:

services.AddTransient<IMyService, MyService>(); 
services.AddScoped<IMyScopedService, MyScopedService>(); 
services.AddSingleton<IMySingletonService, MySingletonService>(); 

Q26. What are Minimal APIs in Dot NET Core?

Minimal APIs are a lightweight way to build APIs in Dot NET Core without using controllers. They provide better performance and are ideal for microservices and small APIs.

Example:

var builder = WebApplication.CreateBuilder(args);
var app = builder.Build();
 
app.MapGet("/", () => "Hello, World!");
 
app.Run();

Q27. What is the difference between IActionResult and ActionResult in ASP Dot NET Core?

IActionResult is an interface that represents the result of an action method in ASP Dot NET Core, which can return various types like OkResult, NotFoundResult, BadRequestResult, etc.

ActionResult is a class that implements IActionResult and allows returning different types of results more easily, with better support for generic results like ActionResult<T>. For example, you can return ActionResult<string> to return both HTTP status and content.

Q28. What is the role of Startup.cs in ASP Dot NET Core?

Startup.cs is the main configuration file in an ASP Dot NET Core application. It contains the application’s setup, such as services registration (using ConfigureServices) and defining the middleware pipeline (using Configure). It helps in configuring things like authentication, routing, logging, and more.

Q29. How does Dot NET Core support asynchronous programming?

Dot NET Core supports asynchronous programming through the async and await keywords. This allows non-blocking I/O operations, improving scalability by freeing up resources while waiting for tasks like file I/O, database queries, or HTTP requests to complete.

Q30. What are NuGet packages in Dot NET Core and how do you use them?

NuGet is the package manager for Dot NET, and it is used to distribute reusable code libraries. In Dot NET Core, you can add NuGet packages to your project by specifying them in the .csproj file or using the NuGet CLI to install and manage dependencies.

Q31. What are some performance optimizations in Dot NET Core?

Dot NET Core offers several performance optimizations such as:

• JIT (Just-In-Time) compilation for faster execution.
• Memory management improvements like low-latency garbage collection.
• Modular framework that allows for only the required dependencies.
• Kestrel server for efficient request handling.

Q32. What is Entity Framework Core and how is it different from Entity Framework?

Entity Framework Core is a lightweight, cross-platform version of the Entity Framework ORM. It supports Dot NET Core applications and is designed to be more modular and optimised for performance compared to the traditional Entity Framework, which is limited to Dot NET Framework and lacks cross-platform support.

It is crucial to practice interview questions on Dot Net Core for many reasons - 

1. Builds Confidence: You can become more confident and comfortable with technical discussions by answering potential questions in advance. The more you practice, the more confident and fluent you become in uttering your thoughts.
2. Improves Understanding: You can easily strengthen your knowledge of core concepts like API development, middleware, and dependency injection with daily practice of interview questions on Net Core. It also aids you in knowing the gaps in your work and understanding how to improve them. 
3. Improves Problem-Solving Skills: Interviewers often evaluate your problem-solving skills by giving you challenging scenarios. Practising many questions helps you build the skills to approach problems systematically and create effective solutions.
4. Time Management: Practicing interview questions helps you tackle your response time effectively throughout the interview. You can make the best impression in the limited available time by knowing how to answer questions confidently and concisely.
5. Stay Updated: Dot Net Core keeps evolving, and practising interview questions based on Net Core 6.0 can align you with industry standards. Knowing about the latest improvements and features will let you showcase yourself as a knowledgeable candidate.
6. Structured Approach: Practicing some important questions provides a structured way to present your ideas concisely and clearly during interviews. It also aids you in developing a logical sequence to explain your answers. This ultimately ensures coherence and clarity.
7. Better Adaptability: Exposure to various types of questions, varying from basic to advanced levels, improves your flexibility to difficulty levels and diverse interview styles. ‍
8. Prepares for Behavioural Questions: Along with technical questions, interviews often comprise behavioural aspects. Practising situational and technical questions helps you effectively present your experiences and abilities.

Below are some detailed tips that will help you prepare for your Dot Net Core interview-

1. Master the Basics: Make sure that you have a great understanding of basic concepts like ASP Dot NET Core architecture, configurations, middleware, and dependency injection. Review tutorials and official documentation to reinforce your foundation.
2. Hands-on Practice: Implement practical exercises and small projects to apply theoretical concepts. Working on real-world situations will also assist you in improving problem-solving skills and building confidence. 
3. Study Common Interview Questions: Prepare frequently asked net core interview questions for freshers that cover areas like API development, authentication, entity framework core, and routing. 
4. Comprehend Design Patterns: Understand key design patterns utilised in Dot Net Core apps, like Repository patterns, Factory, and Singleton. Knowing these subjects will help you answer architecture-related questions efficiently.
5. Stay Updated: Dot Net Core is a subject that keeps changing. Therefore, you need to stay updated about the best practices introduced in the newest versions, performance enhancements, and new features. This includes preparing the latest Net Core 6.0 interview questions.
6. Learn About Cloud Integration: Since Dot Net Core is extensively used in cloud environments, gain insight on deploying applications to cloud platforms like AWS and Azure. As a bonus, you can also learn Kubernetes and Docker. 
7. Develop Coding Skills: Always write maintainable, well-organised, and clean code. You can also try participating in coding challenges on platforms like HackerRank and LeetCode to expand your coding skills. 
8. Mock Interviews: You can also conduct mock interviews with mentors or peers to simulate real interview situations. This will aid you in getting used to answering questions under pressure and enhance your communication skills.
9. Check Official Documentation: Microsoft gives detailed documentation on Dot Net Core topics. You will stay updated with the framework's recommended practices and capabilities when you frequently refer to it. 
10. Identify the Performance Optimisation Techniques: Learn methods to increase your application performance. This includes memory management, asynchronous programming, and caching strategies in Dot Net Core. 
11. Prepare for Behavioural Questions: Along with technical abilities, interviewers may also check your communication, teamwork, and problem-solving approach. Be prepared to discuss your past experiences and previous projects. ‍
12. Realise Testing Strategies: Gain knowledge of integration testing and unit testing in Dot Net Core using frameworks like Moq and xUnit. This will help you display your dedication to writing reliable code.

Preparing for Dot NET core questions and answers requires a well-structured approach that comprises many things. For example, you will need to practice frequently asked questions, stay updated with the recent features, and master basic concepts. Besides technical knowledge, candidates should also develop problem-solving skills, comprehend design patterns, and learn cloud deployment strategies, which can considerably improve their keenness. 

You can also leverage resources like coding challenges, mock interviews, and official documentation to further enhance your performance and build confidence. Remember that preparing for an interview is an ongoing process. This means you need to practice consistently and exert effort to beat the competition. With a strategic way and dedication, you can successfully crack your Dot Net Core interview and progress your career in software development. To get deeper into coding, enroll in the Intensive 3.0 Program. 

1. Explain the core features of Dot NET Core.

Dot Net Core provides modularity, dependency injection, high performance, cross-platform support, built-in support, and open-source nature for cloud integration capabilities and microservices.

2. How can I prep for a Dot NET Core interview?

For effective preparation, you should concentrate on preparing core concepts. You can also participate in mock interviews, stay updated with the latest features, review frequently asked questions, practice coding exercises, etc. 

3. What are the most frequently asked Dot NET Core interview questions for freshers?

Freshers are normally asked questions on the fundamentals. Some common questions include the differences between the Dot NET Framework and Dot NET Core, entity framework, middleware, and dependency injection. 

4. Which tools should I use to practice Dot NET Core coding?

Some common tools include Visual Studio Code, Visual Studio, and online coding platforms like LeetCode. 

5. How crucial is cloud integration knowledge for a Dot NET Core developer?

Cloud integration is important because most modern apps are deployed on cloud platforms, including AWS and Azure.