Top 100 ASP.NET Core Interview Questions and Answers for 2024 PART - 5

41.) What is the difference between VAR and Dynamic keyword?

- VAR is used for implicit type inference at compile time, where the compiler determines the type of a variable based on the assigned value.

- Dynamic is a type in C# that defers type checking until runtime, allowing variables to hold values of any type and enabling late binding and dynamic typing.

42.) Explain the term type safety and casting in C#?

- Type safety refers to the enforcement of type rules by the compiler to prevent invalid type conversions and ensure type correctness at compile time.

- Casting is the process of converting an object from one type to another. In C#, casting can be either implicit or explicit, depending on the compatibility of the types involved.

43.) Explain casting, implicit conversion, and explicit conversion?

- Casting is the explicit conversion of an object from one type to another, typically using the syntax `(Type)expression`.

- Implicit conversion occurs when a value of one type is automatically converted to another compatible type without the need for explicit casting. For example, converting an int to a double.

- Explicit conversion requires the use of a cast operator to convert a value from one type to another. It's used when an implicit conversion is not possible or when the conversion may result in loss of data.

44.) What are stack and heap?

- Stack: A stack is a region of memory used for storing method call frames and local variables. It operates in a Last-In-First-Out (LIFO) manner, where items are added and removed from the top of the stack. The stack is typically used for storing primitive data types and references to objects.

- Heap: The heap is a region of memory used for dynamic memory allocation, where objects are stored. Unlike the stack, memory in the heap is allocated and deallocated dynamically, and objects can exist in the heap for the duration of the program's execution.

45.) What are Value types and Reference types?

- Value types: Value types are data types that store their values directly in memory. They are typically primitive types such as integers, floating-point numbers, and structs. When a value type variable is assigned to another variable or passed as a parameter, a copy of its value is created.

- Reference types: Reference types are data types that store references (memory addresses) to their actual data on the heap. They include classes, arrays, interfaces, and delegates. When a reference type variable is assigned to another variable or passed as a parameter, both variables reference the same underlying data on the heap.

46.) What is the concept of Boxing and Unboxing?

- Boxing: Boxing is the process of converting a value type to a reference type by encapsulating it within an object. When a value type is boxed, a new object is allocated on the heap to hold the value, and a reference to this object is returned.

- Unboxing: Unboxing is the reverse process of boxing, where a boxed value is extracted from its containing object and converted back to its original value type. This involves retrieving the value from the object and assigning it to a variable of the appropriate value type.

47.) How performance is affected due to boxing and unboxing?

- Boxing and unboxing incur performance overhead because they involve additional memory allocation and data copying operations.

- Boxing can lead to memory fragmentation and increased garbage collection overhead, especially when performed frequently in a tight loop.

- Unboxing involves type checking and conversion, which can introduce runtime overhead, especially if performed repeatedly.

48.) How can we avoid boxing and unboxing?

- Avoid using value types in scenarios where they need to be treated as reference types, such as collections or method parameters that expect objects.

- Use generic collections (`List<T>`, `Dictionary<TKey, TValue>`, etc.) instead of non-generic collections to avoid boxing when storing value types.

- Use methods and APIs that operate directly on value types to avoid unnecessary boxing and unboxing operations.

49.) If we have a class referencing value type, where is the value type stored?

- If a class references a value type, the value type is stored on the heap alongside the class object. This is because reference types (such as classes) store references to their data on the heap, regardless of whether the data itself is a value type or a reference type.

50.) Are static variables stored on a heap or stack?

- Static variables are stored neither on the heap nor on the stack. Instead, they are stored in a special area of memory known as the static memory area, which is separate from both the stack and the heap. The static memory area is typically allocated when the program starts and remains in memory for the duration of the program's execution.

Top 100 ASP.NET Core Interview Questions and Answers for 2024 PART - 4

Top 100 ASP.NET Core Interview Questions and Answers for 2024 PART - 4

 

2331.)  What is Delay signing?

 

- Delay signing is a technique used during development to defer the generation of a full strong name for an assembly until it is ready for deployment.

- It allows developers to work with assemblies without requiring access to the full key pair used for strong naming.

 

2632.) What is GAC?

 

- GAC (Global Assembly Cache) is a machine-wide repository in the .NET framework for storing shared assemblies.

- It provides a centralized location for storing and sharing assemblies across multiple applications on the same system.

 

2733.) How to add and remove an assembly from GAC?

 

- Assemblies can be added to the GAC using the Gacutil.exe tool provided by the .NET framework.

- To remove an assembly from the GAC, you can use the same tool with the /u flag followed by the assembly name.

 

34.) If we have two versions of the same assembly in GAC how do we make a choice?

 

- The CLR uses a versioning policy to determine which version of an assembly to load from the GAC.

- By default, the CLR loads the highest available version of the assembly unless a specific version is specified

 

 

2835.) What is Reflection and why we need it?

 

- Reflection is a powerful feature in .NET that allows code to inspect and manipulate the structure of types, members, and objects at runtime.

- It provides the ability to dynamically load assemblies, create instances of types, invoke methods, and access fields and properties, even if they are private.

- Reflection is essential for building dynamic and extensible applications, enabling features such as plugin systems, serialization, and dynamic code generation.

 

2936.) How do we implement reflection?

 

- Reflection is implemented using classes from the System. Reflection namespace in. NET.

- Developers can use classes like Type, MethodInfo, PropertyInfo, and FieldInfo to introspect and manipulate types and members at runtime.

- Reflection involves querying type information, accessing members, and invoking methods dynamically based on runtime conditions.

 

3037.) What are the practical uses of reflection?

 

- Dynamic code generation and execution

- Serialization and deserialization of objects

- Dependency injection and inversion of control containers

- Custom attribute-based metadata processing

- Building extensible frameworks and plugins

 

3138.) What is the use of the Dynamic keyword?

 

- The dynamic keyword in C# enables dynamic typing, allowing variables to hold values of any type at runtime.

- It defers type checking until runtime, providing flexibility in scenarios where the type of an object is not known until runtime.

 

3239.) What are the practical uses of Dynamic keywords?

 

- Interacting with dynamic languages like JavaScript or Python

- Working with COM objects and dynamic APIs

- Parsing dynamic data structures like JSON or XML

 

3340.) What is the difference between Reflection and Dynamic?

 

- Reflection is a mechanism for inspecting and manipulating types, members, and objects at runtime, whereas dynamic is a type in C# that enables dynamic typing and late binding.

 

3441.) Explain the difference between early binding and late binding?

 

- Early binding (also known as static binding) occurs at compile time, where method calls and type resolutions are resolved before the program is executed.

- Late binding (also known as dynamic binding) occurs at runtime, where method calls and type resolutions are deferred until the program is executed, typically using reflection or dynamic typing.

Top 100 ASP.NET Core Interview Questions and Answers for 2024 PART - 3

 Top 100 ASP.NET Core Interview Questions and Answers for 2024 PART - 3

 

1221.) What is a CLS (Common Language Specification)?

 

- CLS (Common Language Specification) is a subset of the CTS that defines a set of rules and guidelines for language interoperability within the .NET framework.

- It ensures that code written in different .NET languages can be easily used and accessed by other .NET languages.

 

1722.) What is an Assembly?

 

- An assembly is a fundamental unit of deployment in the .NET framework, containing compiled code, metadata, and resources needed to execute an application.

- It can be either a DLL (Dynamic Link Library) or an EXE (Executable) file.

 

23.)What are the different types of Assembly?

 

- There are two types of assemblies:

  1. Private Assembly: Installed in the application's directory and accessible only to that application.

  2. Shared Assembly: Installed in the Global Assembly Cache (GAC) and can be accessed by multiple applications.

 

24.)What is Namespace?

 

- A namespace is a way to organize and group related classes, interfaces, and other types within a .NET application.

- It helps prevent naming conflicts and provides better organization and readability of code.

 

25   25.)  What is the Difference between NameSpace and Assembly?

 

- An assembly is a physical grouping of compiled code, metadata, and resources, while a namespace is a logical grouping of related types within code.

- An assembly can contain one or more namespaces, and multiple assemblies can contribute to the same namespace.

 

2626.) What is ILDASM?

 

- ILDASM (IL Disassembler) is a tool provided by the .NET framework for viewing the IL code of a compiled assembly.

- It allows developers to inspect the intermediate language instructions generated by the compiler.

 

2727.) What is Manifest?

 

- A manifest is a metadata component of an assembly that contains information about the assembly's identity, versioning, dependencies, and security permissions.

- It is stored within the assembly and used by the CLR during assembly loading and execution.

 

2828.) Where is the version information stored in an assembly?

 

- The version information of an assembly is stored in its manifest.

- It includes the assembly's version number, which consists of major, minor, build, and revision components.

 

29.) Is versioning applicable to private assemblies?

 

- Yes, versioning applies to both private and shared assemblies.

- Private assemblies can specify version information to manage compatibility and updates within a single application.

 

2   30.) What is the use of strong names?

 

- Strong names are unique identifiers assigned to assemblies to ensure their integrity and prevent tampering.

- They consist of a public key token and a digital signature, which guarantee that the assembly has not been modified since it was signed.

Top 100 ASP.NET Core Interview Questions and Answers for 2024 PART - 2

 Top 100 ASP.NET Core Interview Questions and Answers for 2024 PART - 2

11.) Is it possible to view the IL code?

 

- Yes, it is possible to view the IL code using tools like IL Disassembler (ildasm.exe) or .NET Reflector.

- These tools allow developers to inspect the IL code generated by the compiler and understand how their source code is translated into intermediate language instructions.

 

12.) What is a CLR?

 

- CLR (Common Language Runtime) is the virtual machine component of the .NET framework responsible for executing managed code.

- It provides various services, including memory management, exception handling, type safety, and garbage collection, to ensure the secure and efficient execution of .NET applications.

 

 

13.) Difference between managed and unmanaged code:

 

- Managed Code:

  - Code executed by the Common Language Runtime (CLR) in the .NET framework.

  - Provides automatic memory management, garbage collection, and runtime environment services.

  - Written in high-level languages like C#, VB.NET, or F#.

  - Runs within a managed environment, ensuring safety and security through features like type-safety and memory management.

 

- Unmanaged Code:

  - Code executed directly by the operating system without the assistance of a runtime environment like the CLR.

  - Typically written in low-level languages like C or C++.

  - Developers are responsible for manual memory management, resource allocation, and deallocation.

  - Unmanaged code can directly interact with system resources and hardware, offering more control but also requiring careful handling to avoid memory leaks and security vulnerabilities.

 

14.) What is a garbage collector?

 

- A garbage collector is a component of the CLR responsible for automatic memory management in managed code.

- It identifies and removes objects from memory that are no longer in use, freeing up memory resources and preventing memory leaks.

 

15.) What are generations in Garbage collector (Gen 0, 1 and 2)?

 

- Generations in the garbage collector refer to different categories of objects based on their age and longevity in memory.

- Gen 0: Newly allocated objects reside in Gen 0. These objects are typically short-lived and are collected frequently.

- Gen 1: Objects that survive Gen 0 collections are promoted to Gen 1. These objects have a longer lifespan but are still subject to periodic collections.

- Gen 2: Objects that survive Gen 1 collections are promoted to Gen 2. These objects have the longest lifespan and are collected less frequently.

 

16.)  Garbage collector cleans managed code, how do we clean unmanaged code?

 

- Unmanaged code requires manual memory management, meaning developers must explicitly allocate and deallocate memory resources using functions like malloc() and free() in C or C++.

- Cleaning unmanaged code involves releasing resources using appropriate cleanup mechanisms, such as calling free() to release memory allocated with malloc().

 

17.) But when we create a destructor the performance falls down? So how can we clean unmanaged objects and also maintain performance?

 

- Destructors in C# (denoted by the ~ symbol) are called finalizers and are used to release unmanaged resources.

- However, relying solely on destructors for resource cleanup can impact performance due to the non-deterministic nature of garbage collection.

- To clean unmanaged objects efficiently while maintaining performance, it's recommended to implement the IDisposable interface and use the Dispose() method to explicitly release resources when they are no longer needed.

 

18.) Can we force garbage collector to run?

 

- Yes, you can force the garbage collector to run using the System.GC.Collect() method.

- However, manual garbage collection is generally not recommended as the CLR's automatic garbage collection mechanism is optimized to run at appropriate times based on memory pressure and resource usage.

 

19.) What is the difference between finalize and dispose?

 

- Finalize is a method called by the garbage collector to perform cleanup of unmanaged resources before an object is destroyed.

- Dispose is a method implemented by classes that manage unmanaged resources, allowing developers to explicitly release these resources when they are no longer needed.

- Finalize is non-deterministic and relies on garbage collection, while Dispose provides deterministic cleanup and should be called explicitly by the developer.

 

20.) What is CTS?

 

- CTS (Common Type System) is a standard that defines how types are declared, used, and managed in the .NET framework.

- It ensures interoperability between languages by defining a common set of data types and rules for type interactions.

 

Top 100 ASP.NET Core Interview Questions and Answers for 2024 PART - 3 --- Coming soon

Top 100 ASP.NET Core Interview Questions and Answers for 2024 PART - 1

Top 100 ASP.NET Core Interview Questions and Answers for 2024 PART - 1

An Overview of ASP.NET Interview Questions as well as Responses

ASP.NET is an open-source web framework that uses .Net to create quick and safe web applications and services. The main feature of ASP.NET is that it is a cross-platform framework, which means that you can create ASP.NET web applications with HTML, CSS, Javascript, or JQuery and it can operate on any operating system. ASP.NET Interview Questions and Answers can be found in this tutorial. With the use of ASP.NET training and ASP.NET interview questions and answers, you may create web applications that can be used with any other third-party resources, such as Google, Facebook, or Microsoft.

 1.)     Whats the difference between a .NET and C#?

 

• .NET:

• Comprehensive framework developed by Microsoft.
• Used for building and running applications on Windows, macOS, and Linux.
• Provides libraries, tools, and runtime environments.
• Supports multiple programming languages.

• C#:

• Programming language designed for the .NET framework.
• Object-oriented and modern.
• Offers simplicity, readability, and scalability.
• Used for building various types of applications within the .NET ecosystem.

 

 

 

2.) Differentiate between .NET Framework vs .NET Core vs .NET 5.0:

 

- .NET Framework:

  - Developed by Microsoft.

  - Initially released in 2002.

  - Designed primarily for Windows-based applications.

  - Has a large set of libraries and APIs.

  - Supports ASP.NET Web Forms, MVC, and Windows Forms.

 

- .NET Core:

  - Also developed by Microsoft.

  - First released in 2016.

  - Cross-platform framework, supporting Windows, macOS, and Linux.

  - Lightweight and modular.

  - Designed for modern application development, including cloud-based and microservices architectures.

  - Supports ASP.NET Core for web development and cross-platform console applications.

 

- .NET 5.0:

  - Represents the convergence of .NET Framework and .NET Core.

  - Released in 2020.

  - Unified platform for building all types of applications, including web, desktop, mobile, cloud, and IoT.

  - Continues the cross-platform support introduced in .NET Core.

  - Introduces new features and improvements over previous versions, including performance enhancements and language updates.

 

3.) Difference between managed and unmanaged code:

 

- Managed Code:

  - Code that is executed by the Common Language Runtime (CLR) in the .NET framework.

  - Provides automatic memory management, garbage collection, and runtime environment services.

  - Written in high-level languages like C#, VB.NET, or F#.

  - Managed code runs within a managed environment, ensuring safety and security through features like type-safety and memory management.

 

- Unmanaged Code:

  - Code that is executed directly by the operating system without the assistance of a runtime environment like the CLR.

  - Typically written in low-level languages like C or C++.

  - Developers are responsible for manual memory management, resource allocation, and deallocation.

  - Unmanaged code can directly interact with system resources and hardware, offering more control but also requiring careful handling to avoid memory leaks and security vulnerabilities.

 

 

 

4.) What is IL code?

 

- IL (Intermediate Language) code is the intermediate representation of .NET code generated by the compiler from source code written in languages like C#, VB.NET, or F#.

- It is a platform-independent, CPU-neutral set of instructions that can be executed by the Common Language Runtime (CLR) on any system that supports the .NET framework.

 

5.) Why IL code is not fully compiled?

 

- IL code is not fully compiled into machine code because it needs to be executed in a managed environment by the CLR.

- This allows for platform independence and runtime optimizations based on the target system's architecture and capabilities.

 

6.) Who compiles the IL code and how does it work?

 

- The CLR compiles IL code into native machine code at runtime through a process called Just-In-Time (JIT) compilation.

- This ensures that the code is optimized for the specific hardware and operating system on which it is running.

 

7.) How does JIT compilation work?

 

- JIT compilation occurs dynamically at runtime when a method is called for the first time.

- The CLR analyzes the IL code and generates native machine code tailored to the current execution environment.

- This native code is then executed directly by the CPU, improving performance compared to interpreting IL code.

 

8.) What are the different types of JIT?

 

- There are three types of JIT compilation:

  1. Normal JIT: Compiles methods when they are called at runtime.

  2. Econo JIT: Optimizes compilation time and memory usage by deferring compilation until necessary.

  3. Pre-JIT: Compiles all methods into native code at installation time or startup, producing an executable or assembly with pre-compiled code.

 

9.) What is Native Image Generator (Ngen.exe)?

 

- Ngen.exe is a tool provided by the .NET framework that pre-compiles IL code into native machine code ahead of time.

- It generates native images, which can improve startup performance by reducing the need for JIT compilation at runtime.

 

10.) So does it mean that NGEN.EXE will always improve performance?

 

- While Ngen.exe can improve startup performance by reducing JIT compilation overhead, its impact on overall performance may vary depending on factors such as the application's usage patterns and the target system's configuration.

- It may not always lead to performance improvements in all scenarios.

ASP.NET CACHING RELATED INTERVIEW QUESTIONS WITH ANSWERS Part 3

ASP.NET CACHING RELATED INTERVIEW QUESTIONS WITH ANSWERS Part 3

21. **Explain the difference between absolute and sliding expiration in ASP.NET caching.**

    - **Absolute expiration:** Specifies a fixed duration for which cached data remains valid. After the expiration duration elapses, the cached item is considered stale and needs to be refreshed.

    

    - **Sliding expiration:** Resets the expiration duration each time the cached item is accessed. As long as the item is accessed within the specified sliding expiration period, it remains valid. Sliding expiration is useful for scenarios where data needs to be cached as long as it's actively being used.

22. **What is cache invalidation and why is it important?**

    Cache invalidation refers to the process of removing stale or outdated cached items from the cache to ensure that only fresh and relevant data is served to users. It's important to maintain cache integrity and prevent users from accessing outdated information.

23. **How do you implement cache invalidation strategies in ASP.NET applications?**

    Cache invalidation strategies can include setting appropriate expiration policies, using cache dependencies to monitor changes in underlying data, implementing manual cache invalidation mechanisms, and utilizing cache-clearing techniques when necessary.

24. **Explain the concept of cache stampede and how to mitigate it in ASP.NET applications.**

    Cache stampede, also known as cache thrashing, occurs when multiple requests concurrently attempt to access the same cached item that has expired or been evicted. This can overload the server and degrade performance. Mitigation strategies include using mutexes or locks to prevent simultaneous cache refreshes, implementing staggered expiration times, and employing caching patterns like lazy loading.

25. **What are cache aside (lazy loading) and read-through caching patterns?**

    - **Cache aside (lazy loading):** In this pattern, the application first checks the cache for the requested data. If the data is not found in the cache, it is fetched from the underlying data source, added to the cache, and then returned to the caller. Subsequent requests for the same data will be served from the cache.

    - **Read-through caching:** In this pattern, the application does not directly interact with the cache. Instead, it relies on a caching layer or framework to automatically fetch data from the underlying data source when requested data is not found in the cache. The retrieved data is then cached for future access.

26. **What are cache regions and how are they used in ASP.NET caching?**

    Cache regions allow developers to logically partition cached items into separate groups or namespaces, enabling finer-grained control over cache management and expiration. This helps organize cached data and prevent namespace collisions in multi-tenant or distributed caching scenarios.

27. **Explain the concept of cache coherency and how it relates to distributed caching.**

    Cache coherency refers to the consistency and synchronization of cached data across multiple cache instances or nodes in a distributed caching environment. Maintaining cache coherency ensures that all cache replicas have an up-to-date view of the data and prevents inconsistencies or data staleness.

28. **What are cache-through and write-through caching patterns?**

    - **Cache-through caching:** In this pattern, data is first written to the underlying data source, and then the cache is updated with the newly written data. Subsequent reads for the same data will be served from the cache.

    - **Write-through caching:** In this pattern, data is written to both the cache and the underlying data source simultaneously or in a coordinated manner. This ensures that the cache is always synchronized with the data source, maintaining consistency between cached data and the authoritative data source.

29. **Explain the role of cache size and cache eviction policies in ASP.NET caching.**

    Cache size and eviction policies determine how cached items are managed and removed from memory when the cache reaches its maximum capacity. Eviction policies define rules for selecting which items to remove, such as least recently used (LRU), least frequently used (LFU), or based on custom criteria.

30. **How do you handle cache warming in ASP.NET applications?**

    Cache warming involves pre-populating the cache with frequently accessed or critical data during application startup or idle periods to ensure that the cache is primed and ready to serve requests efficiently. This can be achieved using background tasks, scheduled jobs, or proactive cache loading mechanisms.

ASP.NET CACHING RELATED INTERVIEW QUESTIONS WITH ANSWERS Part 2

10 ASP.NET caching-related interview questions along with answers part 2

11. **What is the role of the ASP.NET Cache object?**

    The ASP.NET Cache object, available in the `System.Web.Caching` namespace, provides a centralized storage mechanism for caching application data. It allows developers to store and retrieve data in memory, enabling faster access and improved performance.

12. **How do you handle cache expiration and eviction in ASP.NET applications?**

    Cache expiration defines the duration for which cached data remains valid before it expires and needs to be refreshed. Cache eviction refers to the process of removing least recently used or stale cached items from memory to make room for new data. Developers can configure expiration policies and eviction algorithms to optimize cache performance and memory usage.

13. **What are the differences between in-process and out-of-process caching?**

    In-process caching stores cached data within the same application process memory, providing faster access but limited scalability and potential memory issues. Out-of-process caching stores cached data externally, allowing multiple application instances to share the same cache and providing better scalability and reliability but with increased latency.

14. **How do you configure distributed caching in ASP.NET applications?**

    Distributed caching involves using external caching solutions like Redis or Memcached to store cached data across multiple servers or instances. Developers can configure caching providers and connection settings in the web.config file and use APIs provided by the caching solution to interact with cached data.

15. **Explain the concept of cache profiles in ASP.NET.**

    Cache profiles allow developers to define predefined caching settings in the web.config file and apply them to ASP.NET pages or user controls using the `@OutputCache` directive. Cache profiles simplify caching configuration and promote consistency across multiple pages or controls.

16. **What is fragment caching, and how is it implemented in ASP.NET?**

    Fragment caching involves caching specific portions or fragments of a web page, such as user controls or HTML markup, instead of caching the entire page. It can be implemented using the `OutputCache` directive with the `VaryByControl` attribute to cache different fragments based on control-specific parameters.

17. **How do you handle cache dependencies on database changes in ASP.NET applications?**

    Cache dependencies on database changes can be managed using the `SqlCacheDependency` class, which establishes a relationship between cached items and database tables or queries. ASP.NET automatically monitors database changes and invalidates cached items when relevant data is modified.

18. **What are the considerations for caching sensitive or confidential data in ASP.NET applications?**

    When caching sensitive or confidential data, developers should ensure that appropriate security measures are in place, such as encrypting cached data, using secure cache storage solutions, and implementing access controls to restrict unauthorized access to cached items.

19. **Explain the role of cache profiles in controlling cacheability and cache settings in ASP.NET applications.**

    Cache profiles allow developers to define cache settings such as duration, location, and dependencies in a centralized location and apply them to multiple pages or controls using the `@OutputCache` directive. This promotes consistency, simplifies configuration, and facilitates maintenance of caching settings.

20. **How do you measure and monitor cache performance in ASP.NET applications?**

    Cache performance can be measured and monitored using performance counters, logging, and profiling tools provided by ASP.NET or third-party monitoring solutions. Developers can track cache hit ratios, eviction rates, memory usage, and other metrics to identify bottlenecks and optimize cache usage.