DotNET Version

Changes in 1.1 on comparison with 1.0

* Built-in support for mobile ASP.NET controls. Previously available as an add-on for .NET Framework, now part of the framework.
* Security changes - enable Windows Forms assemblies to execute in a semi-trusted manner from the Internet, and enable Code Access Security in ASP.NET applications.
* Built-in support for ODBC and Oracle databases. Previously available as an add-on for .NET Framework 1.0, now part of the framework.
* .NET Compact Framework - a version of the .NET Framework for small devices.
* Internet Protocol version 6 (IPv6) support.
* Numerous API changes.

Changes in 2.0 in comparison with 1.1

* Numerous API changes.
* A new hosting API for native applications wishing to host an instance of the .NET runtime. The new API gives a fine grain control on the behavior of the runtime with regards to multithreading, memory allocation, assembly loading and more (detailed reference). It was initially developed to efficiently host the runtime in Microsoft SQL Server, which implements its own scheduler and memory manager.
* Full 64-bit support for both the x64 and the IA64 hardware platforms.
* Language support for generics built directly into the .NET CLR.
* Many additional and improved ASP.NET web controls.
* New data controls with declarative data binding.
* New personalization features for ASP.NET, such as support for themes, skins and webparts.
* .NET Micro Framework - a version of the .NET Framework related to the Smart Personal Objects Technology initiative.
* Partial classes
* Anonymous methods
* Data Tables

Changes since version 3.0

* New language features in C# 3.0 and VB.NET 9.0 compiler
* Adds support for expression trees and lambda methods
* Extension methods
* Expression trees to represent high-level source code at runtime.
* Anonymous types with static type inference
* Language Integrated Query (LINQ) along with its various providers
o LINQ to Objects
o LINQ to XML
o LINQ to SQL
* Paging support for ADO.NET
* ADO.NET synchronization API to synchronize local caches and server side datastores
* Asynchronous network I/O API.
* Peer-to-peer networking stack, including a managed PNRP resolver
* Managed wrappers for Windows Management Instrumentation and Active Directory APIs[25]
* Enhanced WCF and WF runtimes, which let WCF work with POX and JSON data, and also expose WF workflows as WCF services. WCF services can be made stateful using the WF persistence model.
* Support for HTTP pipelining and syndication feeds.
* ASP.NET AJAX is included
* New System.CodeDom namespace.

DOT NET Architecture

Common Language Infrastructure (CLI):
The purpose of the Common Language Infrastructure, or CLI, is to provide a language-neutral platform for application development and execution, including functions for exception handling, garbage collection, security, and interoperability. By implementing the core aspects of the .NET Framework within the scope of the CLI, this functionality will not be tied to a single language but will be available across the many languages supported by the framework. Microsoft's implementation of the CLI is called Common Language Runtime.

Assemblies:
The CIL code is housed in .NET assemblies. As mandated by specification, assemblies are stored in the Portable Executable (PE) format, common on the Windows platform for all DLL and EXE files. The assembly consists of one or more files, one of which must contain the manifest, which has the metadata for the assembly. The complete name of an assembly (not to be confused with the filename on disk) contains its simple text name, version number, culture, and public key token. The public key token is a unique hash generated when the assembly is compiled, thus two assemblies with the same public key token are guaranteed to be identical from the point of view of the framework. A private key can also be specified known only to the creator of the assembly and can be used for strong naming and to guarantee that the assembly is from the same author when a new version of the assembly is compiled (required to add an assembly to the Global Assembly Cache).

Metadata:
All CIL is self-describing through .NET metadata. The CLR checks the metadata to ensure that the correct method is called. Metadata is usually generated by language compilers but developers can create their own metadata through custom attributes. Metadata contains information about the assembly, and is also used to implement the reflective programming capabilities of .NET Framework.

Security:
.NET has its own security mechanism with two general features: Code Access Security (CAS), and validation and verification. Code Access Security is based on evidence that is associated with a specific assembly. Typically the evidence is the source of the assembly (whether it is installed on the local machine or has been downloaded from the intranet or Internet). Code Access Security uses evidence to determine the permissions granted to the code. Other code can demand that calling code is granted a specified permission. The demand causes the CLR to perform a call stack walk: every assembly of each method in the call stack is checked for the required permission; if any assembly is not granted the permission a security exception is thrown.

When an assembly is loaded the CLR performs various tests. Two such tests are validation and verification. During validation the CLR checks that the assembly contains valid metadata and CIL, and whether the internal tables are correct. Verification is not so exact. The verification mechanism checks to see if the code does anything that is 'unsafe'. The algorithm used is quite conservative; hence occasionally code that is 'safe' does not pass. Unsafe code will only be executed if the assembly has the 'skip verification' permission, which generally means code that is installed on the local machine.

.NET Framework uses appdomains as a mechanism for isolating code running in a process. Appdomains can be created and code loaded into or unloaded from them independent of other appdomains. This helps increase the fault tolerance of the application, as faults or crashes in one appdomain do not affect rest of the application. Appdomains can also be configured independently with different security privileges. This can help increase the security of the application by isolating potentially unsafe code. The developer, however, has to split the application into subdomains; it is not done by the CLR.

Class library:
The .NET Framework includes a set of standard class libraries. The class library is organized in a hierarchy of namespaces. Most of the built in APIs are part of either System.* or Microsoft.* namespaces. These class libraries implement a large number of common functions, such as file reading and writing, graphic rendering, database interaction, and XML document manipulation, among others. The .NET class libraries are available to all .NET languages. The .NET Framework class library is divided into two parts: the Base Class Library and the Framework Class Library.

The Base Class Library (BCL) includes a small subset of the entire class library and is the core set of classes that serve as the basic API of the Common Language Runtime.[10] The classes in mscorlib.dll and some of the classes in System.dll and System.core.dll are considered to be a part of the BCL. The BCL classes are available in both .NET Framework as well as its alternative implementations including .NET Compact Framework, Microsoft Silverlight and Mono.

The Framework Class Library (FCL) is a superset of the BCL classes and refers to the entire class library that ships with .NET Framework. It includes an expanded set of libraries, including WinForms, ADO.NET, ASP.NET, Language Integrated Query, Windows Presentation Foundation, Windows Communication Foundation among others. The FCL is much larger in scope than standard libraries for languages like C++, and comparable in scope to the standard libraries of Java.

Memory management:
The .NET Framework CLR frees the developer from the burden of managing memory (allocating and freeing up when done); instead it does the memory management itself. To this end, the memory allocated to instantiations of .NET types (objects) is done contiguously from the managed heap, a pool of memory managed by the CLR. As long as there exists a reference to an object, which might be either a direct reference to an object or via a graph of objects, the object is considered to be in use by the CLR. When there is no reference to an object, and it cannot be reached or used, it becomes garbage. However, it still holds on to the memory allocated to it. .NET Framework includes a garbage collector which runs periodically, on a separate thread from the application's thread, that enumerates all the unusable objects and reclaims the memory allocated to them.

The .NET Garbage Collector (GC) is a non-deterministic, compacting, mark-and-sweep garbage collector. The GC runs only when a certain amount of memory has been used or there is enough pressure for memory on the system. Since it is not guaranteed when the conditions to reclaim memory are reached, the GC runs are non-deterministic. Each .NET application has a set of roots, which are pointers to objects on the managed heap (managed objects). These include references to static objects and objects defined as local variables or method parameters currently in scope, as well as objects referred to by CPU registers. When the GC runs, it pauses the application, and for each object referred to in the root, it recursively enumerates all the objects reachable from the root objects and marks them as reachable. It uses .NET metadata and reflection to discover the objects encapsulated by an object, and then recursively walk them. It then enumerates all the objects on the heap (which were initially allocated contiguously) using reflection. All objects not marked as reachable are garbage. This is the mark phase. Since the memory held by garbage is not of any consequence, it is considered free space. However, this leaves chunks of free space between objects which were initially contiguous. The objects are then compacted together, by using memcpy to copy them over to the free space to make them contiguous again. Any reference to an object invalidated by moving the object is updated to reflect the new location by the GC. The application is resumed after the garbage collection is over.

The GC used by .NET Framework is actually generational. Objects are assigned a generation; newly created objects belong to Generation 0. The objects that survive a garbage collection are tagged as Generation 1, and the Generation 1 objects that survive another collection are Generation 2 objects. The .NET Framework uses up to Generation 2 objects. Higher generation objects are garbage collected less frequently than lower generation objects. This helps increase the efficiency of garbage collection, as older objects tend to have a larger lifetime than newer objects. Thus, by removing older (and thus more likely to survive a collection) objects from the scope of a collection run, fewer objects need to be checked and compacted.

DOT NET Principal design features

Interoperability

Because interaction between new and older applications is commonly required, the .NET Framework provides means to access functionality that is implemented in programs that execute outside the .NET environment. Access to COM components is provided in the System.Runtime.InteropServices and System.EnterpriseServices namespaces of the framework; access to other functionality is provided using the P/Invoke feature.

Common Runtime Engine

The Common Language Runtime (CLR) is the virtual machine component of the .NET framework. All .NET programs execute under the supervision of the CLR, guaranteeing certain properties and behaviors in the areas of memory management, security, and exception handling.

Language Independence

The .NET Framework introduces a Common Type System , or CTS. The CTS defines all possible datatypes and programming constructs supported by the CLR and how they may or may not interact with each other. Because of this feature, the .NET Framework supports the exchange of instances of types between programs written in any of the .NET languages. This is discussed in more detail in Microsoft .NET Languages.

Base Class Library

The Base Class Library (BCL), part of the Framework Class Library (FCL), is a library of functionality available to all languages using the .NET Framework. The BCL provides classes which encapsulate a number of common functions, including file reading and writing, graphic rendering , interaction and XML document manipulation.

Simplified Deployment

The .NET framework includes design features and tools that help manage the installation of computer software to ensure that it does not interfere with previously installed software, and that it conforms to security requirements.

Security

The design is meant to address some of the vulnerabilities, such as buffer overflows , that have been exploited by malicious software. Additionally, .NET provides a common security model for all applications.

Portability

The design of the .NET Framework allows it to theoretically be platform agnostic, and thus cross-platform compatible. That is, a program written to use the framework should run without change on any type of system for which the framework is implemented. Microsoft's commercial implementations of the framework cover Windows, Windows CE , and the Xbox 360 . In addition, Microsoft submits the specifications for the Common Language Infrastructure (which includes the core class libraries, Common Type System , and the Common Intermediate Language ) making them available as open standards. This makes it possible for third parties to create compatible implementations of the framework and its languages on other platforms.

Java Classes and Objects

1.What restrictions are placed on method overloading?

Two methods may not have the same name and argument list but different return types.

2.What is the difference between String and StringBuffer?

String objects are immutable whereas StringBuffer objects are not. StringBuffer unlike Strings support growable and modifiable strings.

3.What is the default value of an object reference declared as an instance variable?

null unless we define it explicitly.

4.Can a private method of a superclass be declared within a subclass?

Sure. A private field or method or inner class belongs to its declared class and hides from its subclasses.
There is no way for private stuff to have a runtime overloading or overriding (polymorphism) features.

5.How can a subclass call a method or a constructor defined in a superclass?

A constructor is a member function of a class that is used to create objects of that class, invoked using the new operator. It has the same name as the class and has no return type. They are only called once, whereas member functions can be called many times. A method is an ordinary member function of a class. It has its own name, a return type (which may be void), and is invoked using the dot operator. Constructor will be automatically invoked when an object is created whereas method has to be called explicitly.

super.method(); is used to call a super class method from a sub class. To call a constructor of the super class, we use the super(); statement as the first line of the subclass’s constructor.

6.Why Java does not support multiple inheritance?

Java does support multiple inheritance via interface implementation.

7.Can a top-level class be private or protected?

No. A top-level class cannot be private or protected. It can have either “public” or no modifier. If it does not have a modifier it is supposed to have a default access. If a top level class is declared as private/protected the compiler will complain that the “modifier private is not allowed here”.

8.Where and how can you use a private constructor?

Private constructor can be used if you do not want any other class to instantiate the class. This concept is generally used in Singleton Design Pattern. The instantiation of such classes is done from a static public method.

9.How are this() and super() used with constructors?

this() is used to invoke a constructor of the same class. super() is used to invoke a superclass constructor.

10.What is Method Overriding? What restrictions are placed on method overriding?

When a class defines a method using the same name, return type, and argument list as that of a method in its superclass, the method in the subclass is said to override the method present in the Superclass. When the method is invoked for an object of the
class, it is the new definition of the method that is called, and not the method definition from superclass.
Restrictions placed on method overriding
• Overridden methods must have the same name, argument list, and return type.
• The overriding method may not limit the access of the method it overrides. Methods may be overridden to be more public, not more private.
• The overriding method may not throw any exceptions that may not be thrown by the overridden method.

11.Differentiate between a Class and an Object?

The Object class is the highest-level class in the Java class hierarchy. The Class class is used to represent the classes and interfaces that are loaded by a Java program. The Class class is used to obtain information about an object’s design. A Class is only a definition or prototype of real life object. Whereas an object is an instance or living representation of real life object. Every object belongs to a class and every class contains one or more related objects.

12.What is singleton pattern?

This design pattern is used by an application to ensure that at any time there is only one instance of a class created. You can achieve this by having the private constructor in the class and having a getter method which returns an object of the class and creates one for the first time if its null.

13.What is method overloading and method overriding?

Method overloading: When 2 or more methods in a class have the same method names with different arguments, it is said to be method overloading. Overloading does not block inheritance from the superclass. Overloaded methods must have different method signatures

Method overriding : When a method in a class has the same method name with same arguments as that of the superclass,
it is said to be method overriding. Overriding blocks inheritance from the superclass. Overridden methods must have same signature.

Basically overloading and overriding are different aspects of polymorphism.

static/early binding polymorphism: overloading
dynamic/late binding polymorphism: overriding

14.If a class is declared without any access modifiers, where may the class be accessed?

A class that is declared without any access modifiers is said to have package or default access. This means that the class can only be accessed by other classes and interfaces that are defined within the same package.

15.Does a class inherit the constructors of its superclass?

A class does not inherit constructors from any of its super classes.

16.Which java.util classes and interfaces support event handling?

The EventObject class and the EventListener interface support event processing

17.Can an object’s finalize() method be invoked while it is reachable?

An object’s finalize() method cannot be invoked by the garbage collector while the object is still reachable. However, an object’s finalize() method may be invoked by other objects.

18.What is the purpose of the Runtime class?

The purpose of the Runtime class is to provide access to the Java runtime system.

It returns the runtime information like memory availability.

* Runtime.freeMemory() –> Returns JVM Free Memory
* Runtime.maxMemory() –> Returns the maximum amount of memory that the JVM will attempt to use. It also helps to run the garbage collector
* Runtime.gc()

19.What is the purpose of the System class?

The purpose of the System class is to provide access to system resources.

20.Can an unreachable object become reachable again?

An unreachable object may become reachable again. This can happen when the object’s finalize() method is invoked and the object performs an operation which causes it to become accessible to reachable object.

21.What is a bean? Where can it be used?

A Bean is a reusable and self-contained software component. Beans created using java take advantage of all the security and platform independent features of java. Bean can be plugged into any software application. Bean is a simple class which has set and get methods. It could be used within a JSP using JSP tags to use them.

22.What is the functionality of instanceOf() ?
instanceOf opertaor is used to check whether an object can be cast to a specific type without throwing ClassCastException.

23.What would happen if you say this = null?

It will come up with Error Message

“The left-hand side of an assignment must be a variable”.

24.What is the difference between an object and an instance?

An Object May not have a class definition. eg int a[] where a is an array.

An Instance should have a class definition.

eg MyClass my=new MyClass();

my is an instance.

25.What is heap in Java?

It is a memory area which stores all the objects created by an executing program.

Speed Optimiser in .NET

Content of the Speed Optimiser

ABAP interview questions and answers

1. What is an ABAP data dictionary?- ABAP 4 data dictionary describes the logical structures of the objects used in application development and shows how they are mapped to the underlying relational database in tables/views.
2. What are domains and data element?- Domains:Domain is the central object for describing the technical characteristics of an attribute of an business objects. It describes the value range of the field. Data Element: It is used to describe the semantic definition of the table fields like description the field. Data element describes how a field can be displayed to end-user.
3. What is foreign key relationship?- A relationship which can be defined between tables and must be explicitly defined at field level. Foreign keys are used to ensure the consistency of data. Data entered should be checked against existing data to ensure that there are now contradiction. While defining foreign key relationship cardinality has to be specified. Cardinality mentions how many dependent records or how referenced records are possible.
4. Describe data classes.- Master data: It is the data which is seldomly changed. Transaction data: It is the data which is often changed. Organization data: It is a customizing data which is entered in the system when the system is configured and is then rarely changed. System data:It is the data which R/3 system needs for itself.
5. What are indexes?- Indexes are described as a copy of a database table reduced to specific fields. This data exists in sorted form. This sorting form ease fast access to the field of the tables. In order that other fields are also read, a pointer to the associated record of the actual table are included in the index. Yhe indexes are activated along with the table and are created automatically with it in the database.
6. Difference between transparent tables and pooled tables.- Transparent tables: Transparent tables in the dictionary has a one-to-one relation with the table in database. Its structure corresponds to single database field. Table in the database has the same name as in the dictionary. Transparent table holds application data. Pooled tables. Pooled tables in the dictionary has a many-to-one relation with the table in database. Table in the database has the different name as in the dictionary. Pooled table are stored in table pool at the database level.
7. What is an ABAP/4 Query?- ABAP/4 Query is a powerful tool to generate simple reports without any coding. ABAP/4 Query can generate the following 3 simple reports: Basic List: It is the simple reports. Statistics: Reports with statistical functions like Average, Percentages. Ranked Lists: For analytical reports. - For creating a ABAP/4 Query, programmer has to create user group and a functional group. Functional group can be created using with or without logical database table. Finally, assign user group to functional group. Finally, create a query on the functional group generated.
8. What is BDC programming?- Transferring of large/external/legacy data into SAP system using Batch Input programming. Batch input is a automatic procedure referred to as BDC(Batch Data Communications).The central component of the transfer is a queue file which receives the data vie a batch input programs and groups associated data into “sessions”.
9. What are the functional modules used in sequence in BDC?- These are the 3 functional modules which are used in a sequence to perform a data transfer successfully using BDC programming: BDC_OPEN_GROUP - Parameters like Name of the client, sessions and user name are specified in this functional modules. BDC_INSERT - It is used to insert the data for one transaction into a session. BDC_CLOSE_GROUP - This is used to close the batch input session.
10. What are internal tables?- Internal tables are a standard data type object which exists only during the runtime of the program. They are used to perform table calculations on subsets of database tables and for re-organising the contents of database tables according to users need.
11. What is ITS? What are the merits of ITS?- ITS is a Internet Transaction Server. ITS forms an interface between HTTP server and R/3 system, which converts screen provided data by the R/3 system into HTML documents and vice-versa. Merits of ITS: A complete web transaction can be developed and tested in R/3 system. All transaction components, including those used by the ITS outside the R/3 system at runtime, can be stored in the R/3 system. The advantage of automatic language processing in the R/3 system can be utilized to language-dependent HTML documents at runtime.
12. What is DynPro?- DynPro is a Dynamic Programming which is a combination of screen and the associated flow logic Screen is also called as DynPro.
13. What are screen painter and menu painter?- Screen painter: Screen painter is a tool to design and maintain screen and its elements. It allows user to create GUI screens for the transactions. Attributes, layout, filed attributes and flow logic are the elements of Screen painter. Menu painter: Menu painter is a tool to design the interface components. Status, menu bars, menu lists, F-key settings, functions and titles are the components of Menu painters. Screen painter and menu painter both are the graphical interface of an ABAP/4 applications.
14. What are the components of SAP scripts?- SAP scripts is a word processing tool of SAP which has the following components: Standard text. It is like a standard normal documents. Layout sets. - Layout set consists of the following components: Windows and pages, Paragraph formats, Character formats. Creating forms in the R/3 system. Every layout set consists of Header, paragraph, and character string. ABAP/4 program.
15. What is ALV programming in ABAP? When is this grid used in ABAP?- ALV is Application List viewer. Sap provides a set of ALV (ABAP LIST VIEWER) function modules which can be put into use to embellish the output of a report. This set of ALV functions is used to enhance the readability and functionality of any report output. Cases arise in sap when the output of a report contains columns extending more than 255 characters in length. In such cases, this set of ALV functions can help choose selected columns and arrange the different columns from a report output and also save different variants for report display. This is a very efficient tool for dynamically sorting and arranging the columns from a report output. The report output can contain up to 90 columns in the display with the wide array of display options.
16. What are the events in ABAP/4 language?- Initialization, At selection-screen, Start-of-selection, end-of-selection, top-of-page, end-of-page, At line-selection, At user-command, At PF, Get, At New, At LAST, AT END, AT FIRST.
17. What is CTS and what do you know about it?- The Change and Transport System (CTS) is a tool that helps you to organize development projects in the ABAP Workbench and in Customizing, and then transport the changes between the SAP Systems and clients in your system landscape. This documentation provides you with an overview of how to manage changes with the CTS and essential information on setting up your system and client landscape and deciding on a transport strategy. Read and follow this documentation when planning your development project.
18. What are logical databases? What are the advantages/ dis-advantages of logical databases?- To read data from a database tables we use logical database. A logical database provides read-only access to a group of related tables to an ABAP/4 program. Advantages: i)check functions which check that user input is complete, correct,and plausible. ii)Meaningful data selection. iii)central authorization checks for database accesses. iv)good read access performance while retaining the hierarchical data view determined by the application logic. dis advantages: i)If you donot specify a logical database in the program attributes,the GET events never occur. ii)There is no ENDGET command,so the code block associated with an event ends with the next event statement (such as another GET or an END-OF-SELECTION).
19. What is a batch input session?- BATCH INPUT SESSION is an intermediate step between internal table and database table. Data along with the action is stored in session ie data for screen fields, to which screen it is passed, program name behind it, and how next screen is processed.
20. How to upload data using CATT ?- These are the steps to be followed to Upload data through CATT: Creation of the CATT test case & recording the sample data input. Download of the source file template. Modification of the source file. Upload of the data from the source file.
21. What is Smart Forms?- Smart Forms allows you to create forms using a graphical design tool with robust functionality, color, and more. Additionally, all new forms developed at SAP will be created with the new Smart Form solution.
22. How can I make a differentiation between dependent and independent data?- Client dependent or independent transfer requirements include client specific or cross client objects in the change requests. Workbench objects like SAPscripts are client specific, some entries in customizing are client independent. If you display the object list for one change request, and then for each object the object attributes, you will find the flag client specific. If one object in the task list has this flag on, then that transport will be client dependent.
23. What is the difference between macro and subroutine?- Macros can only be used in the program the are defined in and only after the definition are expanded at compilation / generation. Subroutines (FORM) can be called from both the program the are defined in and other programs . A MACRO is more or less an abbreviation for some lines of code that are used more than once or twice. A FORM is a local subroutine (which can be called external). A FUNCTION is (more or less) a subroutine that is called external. Since debugging a MACRO is not really possible, prevent the use of them (I’ve never used them, but seen them in action). If the subroutine is used only local (called internal) use a FORM. If the subroutine is called external (used by more than one program) use a FUNCTION.

C# interview questions and answers

1. What’s the advantage of using System.Text.StringBuilder over System.String? StringBuilder is more efficient in the cases, where a lot of manipulation is done to the text. Strings are immutable, so each time it’s being operated on, a new instance is created.
2. Can you store multiple data types in System.Array? No.
3. What’s the difference between the System.Array.CopyTo() and System.Array.Clone()? The first one performs a deep copy of the array, the second one is shallow.
4. How can you sort the elements of the array in descending order? By calling Sort() and then Reverse() methods.
5. What’s the .NET datatype that allows the retrieval of data by a unique key? HashTable.
6. What’s class SortedList underneath? A sorted HashTable.
7. Will finally block get executed if the exception had not occurred? Yes.
8. What’s the C# equivalent of C++ catch (…), which was a catch-all statement for any possible exception? A catch block that catches the exception of type System.Exception. You can also omit the parameter data type in this case and just write catch {}.
9. Can multiple catch blocks be executed? No, once the proper catch code fires off, the control is transferred to the finally block (if there are any), and then whatever follows the finally block.
10. Why is it a bad idea to throw your own exceptions? Well, if at that point you know that an error has occurred, then why not write the proper code to handle that error instead of passing a new Exception object to the catch block? Throwing your own exceptions signifies some design flaws in the project.
11. What’s a delegate? A delegate object encapsulates a reference to a method. In C++ they were referred to as function pointers.
12. What’s a multicast delegate? It’s a delegate that points to and eventually fires off several methods.
13. How’s the DLL Hell problem solved in .NET? Assembly versioning allows the application to specify not only the library it needs to run (which was available under Win32), but also the version of the assembly.
14. What are the ways to deploy an assembly? An MSI installer, a CAB archive, and XCOPY command.
15. What’s a satellite assembly? When you write a multilingual or multi-cultural application in .NET, and want to distribute the core application separately from the localized modules, the localized assemblies that modify the core application are called satellite assemblies.
16. What namespaces are necessary to create a localized application? System.Globalization, System.Resources.
17. What’s the difference between // comments, /* */ comments and /// comments? Single-line, multi-line and XML documentation comments.
18. How do you generate documentation from the C# file commented properly with a command-line compiler? Compile it with a /doc switch.
19. What’s the difference between and XML documentation tag? Single line code example and multiple-line code example.
20. Is XML case-sensitive? Yes, so and are different elements.
21. What debugging tools come with the .NET SDK? CorDBG – command-line debugger, and DbgCLR – graphic debugger. Visual Studio .NET uses the DbgCLR. To use CorDbg, you must compile the original C# file using the /debug switch.
22. What does the This window show in the debugger? It points to the object that’s pointed to by this reference. Object’s instance data is shown.
23. What does assert() do? In debug compilation, assert takes in a Boolean condition as a parameter, and shows the error dialog if the condition is false. The program proceeds without any interruption if the condition is true.
24. What’s the difference between the Debug class and Trace class? Documentation looks the same. Use Debug class for debug builds, use Trace class for both debug and release builds.
25. Why are there five tracing levels in System.Diagnostics.TraceSwitcher? The tracing dumps can be quite verbose and for some applications that are constantly running you run the risk of overloading the machine and the hard drive there. Five levels range from None to Verbose, allowing to fine-tune the tracing activities.
26. Where is the output of TextWriterTraceListener redirected? To the Console or a text file depending on the parameter passed to the constructor.
27. How do you debug an ASP.NET Web application? Attach the aspnet_wp.exe process to the DbgClr debugger.
28. What are three test cases you should go through in unit testing? Positive test cases (correct data, correct output), negative test cases (broken or missing data, proper handling), exception test cases (exceptions are thrown and caught properly).
29. Can you change the value of a variable while debugging a C# application? Yes, if you are debugging via Visual Studio.NET, just go to Immediate window.
30. Explain the three services model (three-tier application). Presentation (UI), business (logic and underlying code) and data (from storage or other sources).
31. What are advantages and disadvantages of Microsoft-provided data provider classes in ADO.NET? SQLServer.NET data provider is high-speed and robust, but requires SQL Server license purchased from Microsoft. OLE-DB.NET is universal for accessing other sources, like Oracle, DB2, Microsoft Access and Informix, but it’s a .NET layer on top of OLE layer, so not the fastest thing in the world. ODBC.NET is a deprecated layer provided for backward compatibility to ODBC engines.
32. What’s the role of the DataReader class in ADO.NET connections? It returns a read-only dataset from the data source when the command is executed.
33. What is the wildcard character in SQL? Let’s say you want to query database with LIKE for all employees whose name starts with La. The wildcard character is %, the proper query with LIKE would involve ‘La%’.
34. Explain ACID rule of thumb for transactions. Transaction must be Atomic (it is one unit of work and does not dependent on previous and following transactions), Consistent (data is either committed or roll back, no “in-between” case where something has been updated and something hasn’t), Isolated (no transaction sees the intermediate results of the current transaction), Durable (the values persist if the data had been committed even if the system crashes right after).
35. What connections does Microsoft SQL Server support? Windows Authentication (via Active Directory) and SQL Server authentication (via Microsoft SQL Server username and passwords).
36. Which one is trusted and which one is untrusted? Windows Authentication is trusted because the username and password are checked with the Active Directory, the SQL Server authentication is untrusted, since SQL Server is the only verifier participating in the transaction.
37. Why would you use untrusted verificaion? Web Services might use it, as well as non-Windows applications.
38. What does the parameter Initial Catalog define inside Connection String? The database name to connect to.
39. What’s the data provider name to connect to Access database? Microsoft.Access.
40. What does Dispose method do with the connection object? Deletes it from the memory.
41. What is a pre-requisite for connection pooling? Multiple processes must agree that they will share the same connection, where every parameter is the same, including the security settings.