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Web Services Interview Questions
Web Services work on client-server model where client applications can access web services over the network. Web services provide endpoint URLs and expose methods that can be accessed over network through client programs written in java, shell script or any other different technologies.

Web services are stateless and doesn’t maintain user session like web applications.
There are basically two types of web services : 
 
 
SOAP (Simple Object Access Protocol) Web Services : It is also referred to as transport-independent messaging protocol whose main purpose is to transfer a message, and is based on XML protocol. 
 
RESTful (Representational State Transfer) Web Services : It is developed to fulfill the shortcomings of SOAP and to make the web services more effective.
Some of the important features of web services include : 
 
* Used to standardized XML messaging system. 
* Discoverable via a simple find mechanism. 
* Available over the internet or private networks. 
* Can be synchronous or asynchronous. 
* Supports RPC (Remote Procedure Calls).
* Supports loosely coupled connections between systems. 
* Not tied to any one programming language or any operating system. 
* Supports the transparent exchange of data to facilitate business integration. 
* Supports communication among different apps with HTML, XML, WSDL, SOAP, etc. 
There are various components of web services as given below : 
 
* SOAP (Simple Object Access Protocol) 
* UDDI (Universal Description, Discovery, and Integration) 
* WSDL (Web Services Description Language) 
* RDF (Resource Description Framework) 
* XML (Extensible Markup Language)
The SOAP stands for Simple Object Access Protocol. It is an XML-based protocol for accessing web services. It is platform independent and language independent. By using SOAP, you can interact with other programming language applications.
These are some of the important advantages of SOAP web services :
 
WS Security : SOAP defines its security known as WS Security.

Language Independent : Its web services can be written in any programming language.

Platform Independent : Its web services can be executed on any platform.
These are some of the important disadvantages of SOAP web services :
 
Slow : It uses XML format that must be parsed to be read and defines many standards that must be followed while developing the SOAP applications. So it is slow and consumes more bandwidth and resource.

WSDL Dependent : It uses WSDL and doesn't have any other mechanism to discover the service.
The following list specifies the features of SOAP :
 
* SOAP is a communication protocol.
* SOAP communicates between applications.
* SOAP is a format for sending messages.
* SOAP is designed to communicate via Internet.
* SOAP is platform independent.
* SOAP is language independent.
* SOAP is simple and extensible.
* SOAP allows you to get around firewalls.
* SOAP developed as a W3C standard.
One example of web services is IBM Web Services browser. You can get it from IBM Alphaworks site. This browser shows various demos related to web services. Basically web services can be used with the help of SOAP, WSDL, and UDDI. All these, provide a plug-and-play interface for using web services such as stock-quote service, a traffic-report service, weather service etc.
It is basically set of various protocols that can be used to explore and execute web services. The entire stack has four layers i.e. Service Transport, XML Messaging, Service Description and Service Discovery.