Interview questions for Web Service

1. Define Web Service?

A web service is a kind of software that is accessible on the Internet. It makes use of the XML messaging system and offers an easy to understand, interface for the end users.

2. What the components of a Web Service?

The basic web services platform is XML + HTTP. All the standard web services work using the following components −
• SOAP (Simple Object Access Protocol)
• UDDI (Universal Description, Discovery and Integration)
• WSDL (Web Services Description Language)

3. What is new in this field for past few years?

The initiation of XML in this field is the advancement that provides web service a single language to communicate in between the RPCs, web services and their directories.
user interface to a web service.

4. How Does a Web Service Work?

A web service enables communication among various applications by using open standards such as HTML, XML, WSDL, and SOAP.
You can build a Java-based web service on Solaris that is accessible from your Visual Basic program that runs on Windows.
You can also use C# to build new web services on Windows that can be invoked from your web application that is based on JavaServer Pages (JSP) and runs on Linux.

5. Give me an example of real web service?

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.

6. Define XML – RPC?

It is a protocol that makes use of XML messages to do Remote Procedure Calls.

7. What are the advantages of RESTful web services?

These are some of the important advantages of RESTful web services:
o Fast – The Web Services are fast because there is no strict specification of SOAP. It consumes less bandwidth and resource.
o Language Independent – The web services can be written in any programming language.
o Platform Independent – The web services can be executed on any platform.
o Can use SOAP – The web services can use SOAP web services as the implementation.
o Allows different data format – The web service permits different data format such as Plain Text, HTML, XML, and JSON.

8. Define SOAP?

SOAP is an XML based protocol to transfer between computers.
What is the purpose of SOAP in a web service?
A web service takes the help of SOAP to transfer a message.

9. What are the main features of SOAP?

The following list specifies the features of SOAP:
o SOAP is a communication protocol.
o SOAP communicates between applications.
o SOAP is a format for sending messages.
o SOAP is designed to communicate via Internet.
o SOAP is platform independent.
o SOAP is language independent.
o SOAP is simple and extensible.
o SOAP allows you to get around firewalls.
o SOAP developed as a W3C standard.

10. Define WSDL?

It means Web Services Description Language. It is basically the service description layer in the web service protocol stock. The Service Description layer describes.

11. What is the purpose of XML in a web service?

A web services takes the help of XML to tag the data, format the data.
What is the purpose of WSDL in a web service?
A web service takes the help of WSDL to describe the availability of service.

12.  What is Interoperability in Web services?

The Web services facilitate various applications to communicate with each other and share data and services among themselves. Other applications can also use the web services. For example, a VB or .NET application can communicate with a Java web services and vice versa. Web services are used to make the application platform and technology independent.

13. Explain the loosely coupled architecture of web services?

A consumer of a web service is not tied to that web service directly. The web service interface can change over time without compromising the client’s ability to interact with the service. A tightly coupled system implies that the client and server logic are closely tied to one another, implying that if one interface changes, the other must be updated. Adopting a loosely coupled architecture tends to make software systems more manageable and facilitates simpler integration between different systems.

14. What are the advantages of having XML based Web services?

Using XML eliminates any networking, operating system, or platform binding. So Web Services based applications are highly interoperable application at their core level.

15. Explain features of XML-RPC?

The major features of XML-RPC are enlisted below:
• RPCs are performed using simple XML language.
• XML encoded requests are sent via HTTP POST.
• XML response is embedded in HTTP response.
• It is considered as platform-independent.
• It allows communication between diverse applications.
• It uses HTTP protocol for passing information between client and server computers.
• It has small XML vocabulary for describing request and response’s nature.

16. Enlist a few advantages of web services?

We have already discussed web services, its architecture, components. Now, let us see some of its advantages:
• Every application is now on the internet and it the web service which provides some sort of required functionality to the client applications.
• Web services help in exposing the existing functionalities over the network to help other applications to use in their programs.
• It has features like ‘Interoperability’ which determines the communication between various applications, sharing of data as well as services among themselves.
• Web services use the standardized web service protocol stack for communication which consists of 4 layers namely, Service Transport, XML messaging, Service description and Service discovery.
• It has the feature of the low cost of communication because of the usage of SOAP (Simple Object Access Protocol) over HTTP protocol.
• Easy to deploy, integrate and is reusable.
• Allows simple integration between different feature as a part of the loose coupling feature.