Building a Web Service Powered JSR 168 Financial Portlet

An increasing number of web applications built today use portal
technology. A portal is a web application that typically provides
services such as personalization, single sign-on, and content
aggregation from different sources. Commercially available Java Portal
Web Servers include BEA, IBM, and Oracle, but there are also many open
source Java Portal Web Servers such as Liferay, Pluto, Stringbeans,
and JBoss Portal. Most of these Java Portal Web Servers have tools
that allow you to build portlets. In the early days of portals, you
had to develop and maintain a separate version of your portlet that
complied with the vendor-specific portlet API for each and every
vendor portal. Maintaining separate vendor-specific versions was time
consuming, aggravating, and cumbersome, and limited the availability
of generic, cross-server portlets. Java Specifiction Request #168
(JSR 168) has solved this vendor-specific portlet configuration
problem. By adhering to the standards, you can now build portlets
that can run in portals irrespective of their vendors. Most Java
Portal Web Servers support the JSR 168 specification. This article
concentrates on the presentation and service layers of a Portal Web
Server. The presentation layer interacts with services to aggregate
data from different sources. These services are typically defined in
the service layer and are part of any Service-Oriented Architecture
(SOA) implemented in a portal. MORE INFO