What is an application server?

An application server is a software engine that delivers applications to client computers or devices. The application server runs your server code. Some well known application servers are IIS (Microsoft), WebLogic Server (BEA), JBoss (Red Hat), WebSphere (IBM).

What is a base class and derived class?

A class is a template for creating an object. The class from which other classes derive fundamental functionality is called a base class. For e.g. If Class Y derives from Class X, then Class X is a base class.

The class which derives functionality from a base class is called a derived class. If Class Y derives from Class X, then Class Y is a derived class.

What is an extender class?

An extender class allows you to extend the functionality of an existing control. It is used in Windows forms applications to add properties to controls.

What is inheritance?

Inheritance represents the relationship between two classes where one type derives functionality from a second type and then extends it by adding new methods, properties, events, fields and constants.
C# support two types of inheritance:
· Implementation inheritance
· Interface inheritance

What is implementation and interface inheritance?

When a class (type) is derived from another class(type) such that it inherits all the members of the base type it is Implementation Inheritance.
When a type (class or a struct) inherits only the signatures of the functions from another type it is Interface Inheritance.
In general Classes can be derived from another class, hence support Implementation inheritance. At the same time Classes can also be derived from one or more interfaces. Hence they support Interface inheritance.

What is inheritance hierarchy?

The class which derives functionality from a base class is called a derived class. A derived class can also act as a base class for another class. Thus it is possible to create a tree-like structure that illustrates the relationship between all related classes. This structure is known as the inheritance hierarchy.

Explain Different Types of Constructors in C#?

There are four different types of constructors you can write in a class -
1. Default Constructor
2. Parameterized Constructor
3. Copy Constructor
4. Static Constructor

Define Overriding?

Overriding is a concept where a method in a derived class uses the same name, return type, and arguments as a method in its base class. In other words, if the derived class contains its own implementation of the method rather than using the method in the base class, the process is called overriding.

What is an Interface?

An interface is a standard or contract that contains only the signatures of methods or events. The implementation is done in the class that inherits from this interface. Interfaces are primarily used to set a common standard or contract.

What are functional and non-functional requirements?

Functional requirements defines the behavior of a system whereas non-functional requirements specify how the system should behave; in other words they specify the quality requirements and judge the behavior of a system.
E.g.
Functional - Display a chart which shows the maximum number of products sold in a region.
Non-functional – The data presented in the chart must be updated every 5 minutes.

What is a stack? What is a heap? What is instrumentation?

What is code review? What is logging?

The process of  examining the source code generally through a peer, to verify it against best practices.
Logging is the process of persisting information about the status of an application.

What are mock-ups?

Mock-ups are a set of designs in the form of screens, diagrams, snapshots etc., that helps verify the design and acquire feedback about the application’s requirements and use cases, at an early stage of the design process.

What is .NET Framework?

NET Framework is a complete environment that allows developers to develop, run, and deploy the following applications:
•    Console applications
•    Windows Forms applications
•    Windows Presentation Foundation (WPF) applications
•    Web applications (ASP.NET applications)
•    Web services
•    Windows services
•    Service-oriented applications using Windows Communication Foundation (WCF)
•    Workflow-enabled applications using Windows Workflow Foundation (WF)

What are the main components of .NET Framework?

.NET Framework provides enormous advantages to software developers in comparison to the advantages provided by other platforms. Microsoft has united various modern as well as existing technologies of software development in .NET Framework. These technologies are used by developers to develop highly efficient applications for modern as well as future business needs. The following are the key components of .NET Framework:
•    .NET Framework Class Library
•    Common Language Runtime
•    Dynamic Language Runtimes (DLR)
•    Application Domains
•    Runtime Host
•    Common Type System
•    Metadata and Self-Describing Components
•    Cross-Language Interoperability
•    .NET Framework Security
•    Profiling
•    Side-by-Side Execution

List the new features added in .NET Framework 4.0.

The following are the new features of .NET Framework 4.0:
•    Improved Application Compatibility and Deployment Support
•    Dynamic Language Runtime
•    Managed Extensibility Framework
•    Parallel Programming framework
•    Improved Security Model
•    Networking Improvements
•    Improved Core ASP.NET Services
•    Improvements in WPF 4
•    Improved Entity Framework (EF)
•    Integration between WCF and WF

What is an IL?

Intermediate Language is also known as MSIL (Microsoft Intermediate Language) or CIL (Common Intermediate Language). All .NET source code is compiled to IL. IL is then converted to machine code at the point where the software is installed, or at run-time by a Just-In-Time (JIT) compiler.

What are code contracts?

Code contracts help you to express the code assumptions and statements stating the behavior of your code in a language-neutral way. The contracts are included in the form of pre-conditions, post-conditions and object-invariants. The contracts help you to improve-testing by enabling run-time checking, static contract verification, and documentation generation.

State the differences between the Dispose() and Finalize().

CLR uses the Dispose and Finalize methods to perform garbage collection of run-time objects of .NET applications.

The Finalize method is called automatically by the runtime. CLR has a garbage collector (GC), which periodically checks for objects in heap that are no longer referenced by any object or program. It calls the Finalize method to free the memory used by such objects. The Dispose method is called by the programmer. Dispose is another method to release the memory used by an object. The Dispose method needs to be explicitly called in code to dereference an object from the heap. The Dispose method can be invoked only by the classes that implement the IDisposable interface.

How does CAS works?

There are two key concepts of CAS security policy- code groups and permissions. A code group contains assemblies in it in a manner that each .NET assembly is related to a particular code group and some permissions are granted to each code group. For example, using the default security policy, a control downloaded from a Web site belongs to the Zone, Internet code group, which adheres to the permissions defined by the named permission set. (Normally, the named permission set represents a very restrictive range of permissions.)

Assembly execution involves the following steps:
1.    Evidences are gathered about assembly.
2.    Depending on the gathered evidences, the assembly is assigned to a code group.
3.    Security rights are allocated to the assembly, depending on the code group.
4.    Assembly runs as per the rights assigned to it.

What is Difference between NameSpace and Assembly?

Following are the differences between namespace and assembly:
o    Assembly is physical grouping of logical units, Namespace, logically groups classes.
o    Namespace can span multiple assembly.

Mention the execution process for managed code.

A piece of managed code is executed as follows:
o    Choosing a language compiler
o    Compiling the code to MSIL
o    Compiling MSIL to native code
o    Executing the code.

How can you instantiate a tuple?

The following are two ways to instantiate a tuple:
o    Using the new operator. For example,
Tuple<String, int> t = new Tuple<String, int> ("Hellow", 2);
o    Using the Create factory method available in the Tuple class. For example,
Tuple<int, int, int> t = Tuple.Create<int, int, int> (2, 4, 5);

What is Common Language Specification (CLS)?

CLS is a set of basic rules, which must be followed by each .NET language to be a .NET- compliant language. It enables interoperability between two .NET-compliant languages. CLS is a subset of CTS; therefore, the languages supported by CLS can use each other's class libraries similar to their own. Application programming interfaces (APIs), which are designed by following the rules defined in CLS can be used by all .NET-compliant languages.

What is the role of the JIT compiler in .NET Framework?

The JIT compiler is an important element of CLR, which loads MSIL on target machines for execution. The MSIL is stored in .NET assemblies after the developer has compiled the code written in any .NET-compliant programming language, such as Visual Basic and C#.

JIT compiler translates the MSIL code of an assembly and uses the CPU architecture of the target machine to execute a .NET application. It also stores the resulting native code so that it is accessible for subsequent calls. If a code executing on a target machine calls a non-native method, the JIT compiler converts the MSIL of that method into native code. JIT compiler also enforces type-safety in runtime environment of .NET Framework. It checks for the values that are passed to parameters of any method.

For example, the JIT compiler detects any event, if a user tries to assign a 32-bit value to a parameter that can only accept 8-bit value.