Web Services provide loosely coupled communication between enterprise systems.
Web Services also enables the enterprise systems to expose business functions to Web-enabled clients.
Web Services can be accessed by wider variety of Clients.
Web Services provide Security and quality services such as availability, reliability and transactions.

There are two principle models in web services. These are:
Document oriented Model.
Remote procedure call oriented Model.

Web Services can be implemented by two ways
Synchronous Web Services
Asynchronous Web Services.

Web Services should be used when you need interoperability across heterogeneous platforms. That is, When you need to expose all or part of your application to other applications on different platforms.
Implementing Web Service make sense when your web services clients are potentially non J2EE enterprise applications.

Web Services

1)What is web Services ?
Getting the services through the web.
2)What is JAX-RPC?
JAX-RPC means java api for xml based RPC is a java api for developing and using web-services.
An RPC based web-service is a collection of procedures that can be called by remote client over the internet.
Ex: A typical RPC based web service is a stock quote service that takes a SOAP request for the price of a specified stock and returns the price via SOAP.
3)Explain about Web Services
A Web service, a server application that implements the procedures that available for clients to call, deployed on server-side container.
A web service can make itself available to potential clients by describing itself in a Web Service Description Language (WSDL) document.
4)What is WSDL?
WSDL is an XML document that gives all pertinent information about web service, the operation that can be called on it, parameters for those operations, and the location of where to send requests.
A web client can use WSDL document to discover the what the service offers and how to access it.
5)Explain some of the features of the web services?
Some of the features of the web services are:
1.Interoperability
Using JAX-RPC, a client written in a language other than Java programming language can access a web service developed and deployed on the Java platform. Conversely,a client written in the Java programming language can communicate with a service that was developed and deployed using some other platform.
2.Ease of use:
Using JAX-RPC makes the user to feel comfortable over the RPC. The internal complicated infrastructure, like marshaling, unmarshaling, and transmission details..etc, will be taken care automatically.
3.Advanced features

6)What makes interoperability is possible?
JAX-RPC support for SOAP and WSDL.
7)What is JAXM?
Java API for Messaging provides a standard way to send XML documents over the Internet from the Java platform. It is based on SOAP 1.1 and SOAP with attachments specifications, which define a basic framework for exchanging XML messages.
8)The features of JAXM over the RPC including JAX-RPC
a) One way(asynchronous)messaging.
b) Routing of message to more than one party.
c) Reliable messaging features such as guarantied delivery.
9)What is JAXR?
Java API for XML registries provides a convenient way to access standard business registries over the Internet. Using JAXR one can register the business registry and one can search for a business registry for other business.
10)Write the difference between XML and HTML?
11)Write the differences bet ween SAX and DOM parsers.