Web Service Interview questions

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What are web services?
Web Services are business logic components which provide functionality via the Internet using standard protocols such as HTTP. Web Services uses Simple Object Access Protocol (SOAP) in order to expose the business functionality.SOAP defines a standardized format in XML which can be exchanged between two entities over standard protocols such as HTTP. SOAP is platform independent so the consumer of a Web Service is therefore completely shielded from any implementation details about the platform exposing the Web Service. For the consumer it is simply a black box of send and receive XML over HTTP. So any web service hosted on windows can also be consumed by any platform.
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What are the communication protocol of Web services?
Web services communcate through SOAP and HTTP protocols. Click on the link to know more about what is soap

What is the format of a SOAP message?
Generally SOAP message has two major sections, Header and Body.

What is UDDI ?
Full form of UDDI is Universal Description, Discovery and Integration. It is a directory that can be used to publish and discover public Web Services. For example tomorrow you wish to pusblish your web site and want to know

What is DISCO ?
DISCO is the abbreviated form of Discovery. It is basically used to club or group common services together on a server and provides links to the schema documents of the services it describes may require

What is WSDL?
Web Service Description Language (WSDL)is a W3C specification which defines XML grammar for describing Web Services.XML grammar describes details such as:- √ Where we can find the Web Service (its URI)? √ What are the methods and properties that service supports? √ Data type support. √ Supported protocols In short its a bible of what the webservice can do.Clients can consume this WSDL and build proxy objects that clients use to communicate with the Web Services. Full WSDL specification is available

What is file extension of Webservices ?
.ASMX is extension for Webservices.

How do you authenticate your web service?
you can use SOAP header to authenticate your web service. You may define a class and added as a SOAP header to the web method. While calling from client this has to be added to the SOAP header and should be passed along with the request.
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Can you overload a web method?
Web methods can be overloaded with the message property of the web method.

What is Web Service Enhancements ?
Web Services Enhancements for Microsoft .NET (WSE) is a .NET class library for building Web services using the latest Web services protocols, including WS-Security, WS-SecureConversation, WS-Trust, and WS-Addressing. WSE allows you to add these capabilities at design time using code or at deployment time through the use of a policy file.

What are the design points to be considered while designing a web service.
The return type of the web service should not be language specific. for exampe if you are building it .Net the return type should not be dataset, rather should be a string or an int which can be understood by all Languages.

Other ASP.Net related interview questions are available at
Set 1 of ASP.Net Interview questions or Asp.Net FAQs
Set 2 of ASP.Net Interview questions or Asp.Net FAQs
Set 3 of ASP.Net Interview questions or ASP.Net FAQs

New features of C# 4.0 is available at C# 4.0 FAQs or C# 4.0
Basic .Net questions are available at .Net Frame works FAQ or .Net interview question