50+ Junior .NET Developer Interview Questions and Answers

StringBuffer is a mutable sequence of characters. It is used to efficiently manipulate strings.

• StringBuffer is a class in Java that allows you to modify strings without creating a new object.

• It is used when you need to concatenate a large number of strings efficiently.

• StringBuffer is synchronized, so it is safe to use in multi-threaded environments.

• It provides methods like append(), insert(), delete(), and reverse() to modify the string.

• Example: StringBuffer sb = new StringBu...read more

ArrayList is a dynamic array that can store objects of any type. It is used to store and manipulate collections of data.

• ArrayList is part of the System.Collections namespace in .NET.

• It can store objects of any type, including value types and reference types.

• It automatically resizes itself as elements are added or removed.

• Elements can be accessed by their index.

• It provides methods for adding, removing, and searching for elements.

• Example: ArrayList names = new ArrayList(); name...read more

Code for prime and odd numbers

• For prime numbers, check if the number is divisible by any number less than itself

• For odd numbers, check if the number is not divisible by 2

• Use loops and conditional statements to implement the checks

• Consider edge cases such as negative numbers and 0

Generics in .NET allow you to create reusable code that can work with different types.

• Generics are declared using the 'generic' keyword followed by the type parameter(s) in angle brackets.

• Example: 'public class MyGenericClass {}'

• You can use multiple type parameters separated by commas.

• Example: 'public class MyGenericClass {}'

• Generics provide type safety and eliminate the need for casting.

• Example: 'List myList = new List();'

Interfaces and abstract methods are used to achieve abstraction and provide a blueprint for classes to implement.

• Interfaces allow for multiple inheritance and provide a contract for classes to adhere to.

• Abstract methods define a method signature without implementation, allowing subclasses to provide their own implementation.

• Interfaces and abstract methods promote code reusability and maintainability.

• Interfaces can be used to achieve loose coupling and dependency injection.

• Exa...read more

The isPostBack property is used in the Page_Load event to determine if the page is being loaded for the first time or if it is a postback.

• The isPostBack property is a boolean property that indicates whether the page is being loaded for the first time or if it is a postback.

• It is commonly used to differentiate between the initial page load and subsequent postbacks.

• This property is useful when you want to perform certain actions only on the initial page load and not on postback...read more

Dependency injection is a design pattern where components are given their dependencies rather than creating them.

• Dependency injection helps in making components loosely coupled, making it easier to test and maintain code.

• There are three main lifetimes for dependencies: transient, scoped, and singleton.

• Transient dependencies are created each time they are requested.

• Scoped dependencies are created once per request.

• Singleton dependencies are created only once and reused througho...read more

Abstract classes can have both abstract and non-abstract methods, while interfaces can only have abstract methods.

• Abstract classes can have constructors, fields, and properties, while interfaces cannot.

• A class can inherit from only one abstract class, but can implement multiple interfaces.

• Abstract classes are used when a class needs to provide a default implementation for some methods, while interfaces are used to define a contract for classes to implement.

• Example: Abstract c...read more

CORS stands for Cross-Origin Resource Sharing, a security feature that allows servers to specify who can access their resources.

• CORS is used to prevent web pages from making requests to a different domain than the one that served the original page.

• It is implemented using HTTP headers like Access-Control-Allow-Origin.

• CORS is commonly used in web development to enable secure cross-origin requests in browsers.

• Example: If a frontend application on domain A wants to make a request...read more

Connected architecture maintains a continuous connection to the database while disconnected architecture connects only when required.

• Connected architecture is suitable for applications that require real-time data updates.

• Disconnected architecture is suitable for applications that require occasional data updates.

• Connected architecture uses DataReader while disconnected architecture uses DataSet.

• Connected architecture is faster but consumes more resources than disconnected arch...read more

Multiple inheritance is not directly supported in C#, but can be achieved using interfaces.

• C# does not support multiple inheritance of classes due to the Diamond Problem

• Multiple inheritance can be achieved using interfaces by implementing multiple interfaces in a class

• Example: public class MyClass : Interface1, Interface2 { }

TFS and GitHub are used for version control and collaboration in software development.

• TFS and GitHub provide version control, allowing developers to track changes and collaborate on code.

• They enable multiple developers to work on the same codebase simultaneously, avoiding conflicts.

• They offer features like branching and merging, making it easier to manage different versions of code.

• TFS and GitHub provide a centralized repository for code, ensuring its availability and backup....read more

DDL and DML are SQL queries used to manipulate databases. DDL is used to create, modify or delete database objects while DML is used to manipulate data.

• DDL stands for Data Definition Language and is used to create, modify or delete database objects like tables, indexes, etc.

• DML stands for Data Manipulation Language and is used to manipulate data in the database like inserting, updating or deleting records.

• DDL queries include CREATE, ALTER and DROP statements while DML queries...read more

Code to reverse a string

• Create an empty string variable to store the reversed string

• Loop through the original string from the end to the beginning

• Append each character to the empty string variable

• Return the reversed string

Dotnet Core offers improved performance, cross-platform compatibility, and open-source flexibility.

• Improved performance compared to traditional .NET Framework

• Cross-platform compatibility allows for development on Windows, macOS, and Linux

• Open-source flexibility enables community contributions and faster updates

• Support for microservices architecture and containerization

• Enhanced security features and easier deployment options

In disconnected architecture, class names should reflect the entities or objects they represent.

• Class names should be meaningful and descriptive.

• They should follow naming conventions, such as PascalCase or camelCase.

• Avoid using abbreviations or acronyms that may not be easily understood.

• Consider using domain-specific terminology to make the class names more intuitive.

• Examples: Customer, Order, Product, Employee

I am proficient in C#, SQL, and JavaScript.

• C#

• SQL

• JavaScript

Code for Fibonacci series

• Declare two variables to store the first two numbers of the series

• Use a loop to generate the next numbers in the series by adding the previous two

• Print or store the generated numbers

Delegates are used to create references to methods and pass them as arguments to other methods.

• Delegates allow for loose coupling between objects

• Delegates can be used to implement callbacks and event handlers

• Delegates can be used to implement the observer pattern

• Delegates can be used to implement the command pattern

• Delegates can be used to implement the strategy pattern

Filters in .NET are used to perform logic before or after an action method is executed.

• Filters can be used for authorization, logging, exception handling, etc.

• Examples include AuthorizeFilter, ActionFilter, ExceptionFilter, ResultFilter.

• Filters can be applied globally, at controller level, or at action level.

Abstract classes in C# provide a way to define common behavior for derived classes while allowing specific implementations.

• Use the 'abstract' keyword to define an abstract class.

• Abstract classes cannot be instantiated and can contain abstract methods that must be implemented by derived classes.

• Derived classes must provide implementations for all abstract methods.

• Abstract classes can also have non-abstract methods and properties.

• Example: abstract class Shape { public abstract ...read more

Yes, Angular is a popular front-end framework for building web applications.

• Angular is developed and maintained by Google.

• It uses TypeScript for building applications.

• It follows the MVC (Model-View-Controller) architecture.

• It provides features like two-way data binding, dependency injection, and directives.

• Examples of popular Angular applications include Gmail, PayPal, and Upwork.

Authentication verifies the identity of a user, while authorization determines what actions a user is allowed to perform.

• Authentication confirms the user's identity through credentials like username and password.

• Authorization controls the access rights of authenticated users to specific resources or actions.

• Example: Logging into a website with a username and password is authentication. Accessing certain pages or features based on user roles is authorization.

Join is a SQL operation that combines rows from two or more tables based on a related column between them.

• Join is used to retrieve data from multiple tables in a single query.

• Common types of joins include inner join, left join, right join, and full outer join.

• Join conditions are specified using the ON keyword followed by the columns to join on.

• Example: SELECT * FROM table1 JOIN table2 ON table1.column = table2.column;

Structured Query Language

• SQL stands for Structured Query Language

• It is a standard language for accessing and manipulating databases

• Commonly used for querying, updating, and managing relational databases

• Examples include SELECT, INSERT, UPDATE, DELETE statements

Middlewares are components that handle requests and responses in the pipeline of a web application.

• Middlewares are software components that are executed in the request-response pipeline of a web application.

• They can intercept, process, or modify incoming requests and outgoing responses.

• Examples include authentication middleware, logging middleware, and error handling middleware.

Partial class is a class that can be split into multiple files, allowing different parts of the class to be defined in different files.

• Partial classes are useful for organizing large classes and separating different concerns.

• All parts of a partial class must use the 'partial' keyword.

• When compiled, all parts of a partial class are combined into a single class definition.

A class is a blueprint for creating objects, while an object is an instance of a class.

• A class defines the properties and behaviors of objects.

• An object is created based on a class, and can have its own unique values for the properties defined in the class.

• Example: Class 'Car' may have properties like 'color' and 'model', while an object of class 'Car' could be 'red Ferrari'.

Signature of multicast delegate

• A multicast delegate is a delegate that can have multiple methods assigned to it

• The signature of a multicast delegate is the same as that of a regular delegate

• The signature includes the return type, name, and parameters of the delegate

First returns the first element of a sequence, while Single returns the only element of a sequence or throws an exception if there is not exactly one element.

• First is used to retrieve the first element of a sequence, while Single is used to retrieve the only element of a sequence.

• First does not throw an exception if there are no elements in the sequence, while Single throws an exception in this case.

• Example: var numbers = new List { 1, 2, 3 }; var firstNumber = numbers.First(...read more

ref and out are both used for passing arguments by reference in C#, but out parameters are not required to be initialized before being passed.

• ref parameters must be initialized before being passed to a method, while out parameters do not need to be initialized

• out parameters are typically used for returning multiple values from a method

• ref parameters can be used for both input and output, while out parameters are typically used for output only

A static class is a class that cannot be instantiated and is used to group related methods and properties.

• Static classes are commonly used for utility classes that contain helper methods.

• They are also used for defining extension methods.

• Example: Math class in C# contains static methods like Math.Max() and Math.Min().

Norm software should be chosen based on its compatibility with the organization's existing systems and its ability to meet specific business needs.

• Consider the software's compatibility with existing systems

• Evaluate the software's ability to meet specific business needs

• Assess the software's ease of use and user interface

• Research the software's reputation and customer reviews

• Compare the software's pricing and licensing options

Polymorphism is the ability of an object to take on many forms.

• Polymorphism allows objects of different classes to be treated as objects of a common superclass.

• There are two types of polymorphism: compile-time (method overloading) and runtime (method overriding).

• Example: Animal class with methods like eat() can be inherited by classes like Dog and Cat, which can override the eat() method.

• Polymorphism helps in achieving flexibility and extensibility in object-oriented programm...read more

An interface in .NET is a reference type that defines a contract for classes to implement certain methods and properties.

• Interfaces contain method signatures but no implementation.

• Classes can implement multiple interfaces.

• Interfaces are used for achieving abstraction and multiple inheritance in .NET.

• Example: 'IComparable' interface in C# is used for comparing objects.

Datatype is a classification of data which tells the compiler or interpreter how the programmer intends to use the data.

• Datatypes specify the type of data that a variable can hold.

• Examples include int (integer), string (text), bool (boolean), etc.

• Different programming languages have different datatypes and rules for their usage.

Inheritance is a concept in object-oriented programming where a class inherits properties and behaviors from another class.

• Allows for code reusability by creating a new class based on an existing class

• Derived class (child class) inherits attributes and methods from a base class (parent class)

• Example: Class Car can inherit properties like color and methods like drive from class Vehicle

Dependency Injection is a design pattern where the dependencies of an object are provided externally rather than created within the object itself.

• Allows for better code reusability and testability

• Reduces coupling between classes

• Promotes separation of concerns

• Example: Instead of creating a database connection within a class, the connection is injected into the class through a constructor or property

An array is a collection of similar data types stored in contiguous memory locations.

• Arrays can be of any data type, including integers, floats, and objects.

• Arrays are indexed starting from 0.

• Arrays can be multidimensional, such as a 2D array.

• Arrays can be dynamically resized using methods like Append or Resize.

• Example: string[] names = {"John", "Jane", "Bob"};

Windows.load is not a standard term in .NET development. It may refer to a custom function or method used in a specific application.

• Windows.load is not a built-in function in .NET framework

• It could be a custom function created by a developer for specific purposes

• Without more context, it is difficult to provide a specific answer

Program to reverse a number

• Convert the number to a string

• Reverse the string using a loop or built-in function

• Convert the reversed string back to a number

Reverse a given string

• Use a loop to iterate through the characters of the string and build a new string in reverse order

• Alternatively, use built-in functions like Array.Reverse() in C#

• Consider edge cases like empty string or null input

MVC is a software architectural pattern used in web development to separate the application into three main components: Model, View, and Controller.

• Model: Represents the data and business logic of the application.

• View: Represents the UI of the application, what the user sees and interacts with.

• Controller: Acts as an intermediary between the Model and View, handling user input and updating the Model accordingly.

• Example: In an MVC application, a user interacts with the View (a ...read more