.NET Questions and Answers

1.	.NET Questions and Answers What is difference between MetaData and Manifest?
	Metadata and Manifest forms an integral part of an assembly( dll / exe ) in .net framework . Out of which Metadata is a mandatory component , which as the name suggests gives the details about various components of IL code viz : Methods , properties , fields , class etc.

2.	What is the top .NET class that everything is derived from?
	System.Object
3.	How is method overriding different from method overloading?
	When overriding a method, you change the behavior of the method for the derived class. Overloading a method simply involves having another method with the same name within the class.

4.	What is a formatter?
	A formatter is an object that is responsible for encoding and serializing data into messages on one end, and deserializing and decoding messages into data on the other end.

5.	What is an ArrayList?
	The ArrayList object is a collection of items containing a single data type values.

6.	What is static member?
	The member defined as static which can be invoked directly from the class level, rather than from its instance.

7.	What is Overloading?
	A process of creating different implementation of a method having a same name as base class, in a derived class. It implements Inheritance.

8.	When do you use virutal keyword?
	When we need to override a method of the base class in the sub class, then we give the virtual keyword in the base class method. This makes the method in the base class to be overridable. Methods, properties, and indexers can be virtual, which means that their implementation can be overridden in derived classes.

9.	What is the purpose of XML Namespaces?
	An XML Namespace is a collection of element types and attribute names. It consists of 2 parts §  The first part is the URI used to identify the namespace §  The second part is the element type or attribute name itself.

10.	What is a constructor?
	A constructor is invoked when you use the new operator, or use the various methods of reflection to create an instance of a class.
11.	What is the difference between System.String and System.StringBuilder classes?
	System.String is immutable, System.StringBuilder was designed with the purpose of having a mutable string where a variety of operations can be performed.

12.	What is the use of JIT ?
	JIT (Just - In - Time) is a compiler which converts MSIL code to Native Code (ie. CPU-specific code that runs on the same computer architecture).

13.	What is the difference between early binding and late binding?
	Calling a non-virtual method, decided at a compile time is known as early binding. Calling a virtual method (Pure Polymorphism), decided at a runtime is known as late binding.

14.	Which method do you invoke on the DataAdapter control to load your generated dataset with data?
	DataAdapter’s fill () method is used to fill load the data in dataset.

15.	What is the purpose of an Assembly?
	An assembly controls many aspects of an application. The assembly handles versioning, type and class scope, security permissions, as well as other metadata including references to other assemblies and resources. The rules described in an assembly are enforced at runtime.

16.	What is Authentication and Authorization?
	Authentication is the process of identifying users. Authentication is identifying/validating the user against the credentials (username and password). Authorization performs after authentication. Authorization is the process of granting access to those users based on identity. Authorization allowing access of specific resource to user.

17.	What are the types of Authentication?
	There are 3 types of Authentication. §  Windows authentication §  Forms authentication §  Passport authentication.

18	What is a Literal Control?
	The Literal control is used to display text on a page. The text is programmable. This control does not let you apply styles to its content.
19.	What are the namespace available in .net?
	Namespace is a logical grouping of class. §  System §  System.Data §  System.IO §  System.Drawing §  System.Windows.Forms §  System.Threading

20.	What is Side-by-Side Execution?
	The CLR allows any versions of the same-shared DLL (shared assembly) to execute at the same time, on the same system, and even in the same process. This concept is known as side-by-side execution.

21.	What are the different types of Caching?
	There are three types of Caching : §  Output Caching §  Fragment Caching §  Data Caching.

22.

What is Reference type and value type?

Reference Type : Reference types are allocated on the managed CLR heap, just like object types. A data type that is stored as a reference to the value’s location. Reference types can be self-describing types, pointer types, or interface types. Value Type : Value types are allocated on the stack just like primitive types in VBScript, VB6 and C/C++. Value types are not instantiated using new go out of scope when the function they are defined within returns.

23.	What is Delegates?
	Delegates are a type-safe, object-oriented implementation of function pointers and are used in many situations where a component needs to call back to the component that is using it.

24.	What is Authentication and Authorization?
	Authentication is the process of identifying users. Authentication is identifying/validating the user against the credentials (username and password). Authorization performs after authentication. Authorization is the process of granting access to those users based on identity. Authorization allowing access of specific resource to user.

25.	What is a Static class?
	Static class is a class which can be used or accessed without creating an instance of the class.

26	What is sealed class?
	Sealed classes are those classes which can not be inherited and thus any sealed class member can not be derived in any other class. A sealed class cannot also be an abstract class.
27.	What are the two main parts of the .NET Framework?
	There are the two main parts of the .NET Framework are : §  The common language runtime (CLR). §  The .NET Framework class library.

28.	What is the advantage of using System.Text.StringBuilder over System.String?
	StringBuilder is more efficient in cases where there is a large amount of string manipulation. Strings are immutable, so each time it's being operated on, a new instance is created.

29.	What is reflection?
	All .NET compilers produce metadata about the types defined in the modules they produce. This metadata is packaged along with the module (modules in turn are packaged together in assemblies), and can be accessed by a mechanism called reflection.

30.	What is an Application Domain? How they get created?
	An Application Domain can be thought of as a lightweight processes controlled by the .Net runtime. Application Domains are usually created by hosts like Windows Shell, ASP.NET and IE. When you run a .NET application from the command-line, the host is the Shell. The Shell creates a new Application Domain for every application.