Web service is a XML-based standard that allows interoperability between different applications on different platforms, for example, a .NET based application on Windows can communicate with a Java based one on Linux. The communication can be done through a set of XML messages over HTTP protocol.
Throughout this article, you will learn how to create and publish a web service, and consume the web service by a command line client. This article supposes you are familiar with basic Java
This post briefly explains the 5 tiers in Java Enterprise Edition.
A web browser, a hand held device or an application which remotely accesses the services of an enterprise application are examples of a Client tier. In other words a Client tier can consists of all the types of components that are clients of an enterprise application.
Filters, Java Servlets, JavaServer Pages, JavaBeans and other utility classes