Java Web Services

Let assume to have a situation where our web application written in java wants to interact with another web application which is written in .net.  So, the question is how these two applications will interact with each other .how we can establish communications between them. The answer is through web services.

Let’s have following scenario where you are developing a web application which shows the pnr status of the traveler so how to make interactions or submit the client query to railways website so that the result of the query will be displayed on your applications.

So, basically we have two types of interactions using web applications. They are

1.       Man to machine (Business 2 Machine): The best example of this type of interaction is ATM where client enter his details and query is processed.

2.       Machine to machine (Business 2 Business): The results of some universities are displayed by indiaresults.com, where india results gets the results of students through processing the client requests from the universities websites using web services technique.

A web service is a api given to make communications between two different technologies or same to interact with each other.

There are two types of web services

1.       SOAP(JAX-WS): Java api for xml web services

2.       REST(JAX-RS): java api for xml restful services

SOAP implementations can be achieved through

1.       Axis2- given by Apache

2.       Metro- given by Oracle

Related terminologies:

WSDL (web-services description language): It is a help file or api which contains details about classes, interfaces, methods, data members etc.Actually it is a xml file contains above details of classes and methods(operations) of a Service provider

Example of Wsdl file of GeoIPService

UDDI: It is a registry or place where WSDL file is stored.

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