1. Introduction:

Web services are becoming more and more popular. Web Services allows you to expose the
functionality of your existing code over the network. Once it is exposed on the network, other
application can use the functionality of your program.

Web Services allows different applications to talk to each other and share data and services among
them. Other applications can also use the services of the web services. For example VB or .NET
application can talk to java web services and vice versa. So, Web services are used to make the
application platform and technology independent.

These days due to complexness the business, organizations are using different technologies like
EAI, EDI, B2B, Portals etc. for distributing computing. Web Services supports all these technologies,
thus helping the business to use existing investments in other technologies.

One of the major benefits is Web services’ ease of integration. You will easily integrate your application
with other pieces of software application i.e. with external data sources. You can run it on all kinds
of machines from desktop to mainframe and from within your enterprise to external sites i.e. Web
services link applications, services, and devices together.

In the above figure “Service Requester” acts as client of the web service and the “Service Provider”
as host of the web service. Client makes a request for the web service to the provider and provider
sends response accordingly.

Service registry acts as a database of web services containing all the information needed to develop
a web client, the definition and uri for web services. You can publish your services to the registry.
Now any client can query the registry and select the service from there.