Java Server Page

JSP technology can be used to create simple, interactive pages that report the time of day or track visit-counts to a page. But this technology also scales well to takes its place in an enterprise-level, multitier application architecture.
Pages created with JSP technology are the server-based, "customer-facing" interface for multitier applications, and provide a flexible, scalable environment for deploying these applications.

On the client side, JSP pages communicate with Web-based clients, including HTML-based browsers. The page manages the browser interaction, sending and receiving requests and information, typically in HTML format.

JSP pages may reside in almost any Web server or application server. The pages have access to the wide range of Java APIs and services, including JDBC^TM technology for database access, JavaMail^TM software for Java technology-based e-mail applications, Java Transaction API for transaction services, and so on.

Enterprise JavaBeans^TM components in the middle tier can manage access to enterprise resources in the data/EIS tier, handling security, authorization, transaction integrity, connection pooling, and data caching. Enterprise JavaBeans and their containers encapsulate the complex logic required for high-performance, highly secure enterprise applications.

The beauty of the JSP architecture is its flexible, adaptable design. The back-end data sources are independent from the application logic, which itself is independent from the browser presentation.

For example, it is easy to add new JDBC technology-compliant data sources to an existing application infrastructure. Likewise, new Web-based applications can be built that access existing resources, without reworking the original data sources. Logic that is built once and encapsulated in beans or Enterprise JavaBeans components can be leveraged for many different applications. And the rich and evolving family of Java APIs means that there are continually expanding options for application integration.

JSP technology is not the first approach for enabling interactive Web pages - rather, it is the next step in the progression of products supporting Web-based clients.

Some of the earlier methods include CGI programs, the mod_perl plug-in for the Apache Web Server, and Microsoft Active Server Pages (ASP). For further discussion of these technologies and their differences from JSP technology, please go to java.sun.com/products/jsp/.

Portability - Pages built with JSP technology are portable across platforms and servers, and work with portable, reusable components.
Easier Maintenance and Development - Because the page design is truly separate from the application logic, JSP enables tiered development and maintenance tasks, so page authors and developers can focus on specific areas of interest without requiring the others' help.

JSP technology builds on the strength of the Java family and the multivendor Java community, extending the core capabilities of the Java platform to create powerful, flexible, and easy-to-maintain dynamic Web pages. JSP technology inherits all of the benefits of the Java language, including platform- and server-independence, a modular and reusable component architecture, and access to the rich family of Java APIs (including JDBC, JavaMail, and Java Transaction Service).

Using JSP technology, organizations can meet their users' needs for up-to-date, high-performance, and reliable Web-based applications, while addressing the overall organizational needs for long-term architectural decisions:

Vendor Independence - Many different Web and application servers support JSP technology, and more are added every day. The JSP specification is the product of the Java Community Process (JCP), an open process used by Sun since 1995 to develop and revise Java technology and specifications in cooperation with the international Java community. The result is a specification, built with the input and support of the major vendors in the market, that does not lock companies into any one vendor's solutions.
Portability - JSP technology is portable across platforms and servers alike, building on the Write Once, Run Anywhere philosophy of the Java language. Not only are the pages themselves portable, but they can access Java technology-based components (beans, customized JSP tags) that are also reusable and portable across platforms.
Flexibility - The multitier architecture using JSP technology is inherently flexible and adaptable. Developers can change data sources, access external data if necessary, and implement new security or authorization methodology - all without affecting "customer-facing" applications. Similarly, new applications can be built without reworking the infrastructure to support them. This enables organizations to adopt new technologies or applications as their business needs change.
Low Cost of Ownership - JSP technology lets page authors handle the ongoing maintenance of dynamic pages without requiring developers to be involved in changes that do not involve application logic. Likewise, JSP custom tag libraries make it easy for developers to distribute advanced application functionality to a wide variety of page authors. And, as part of the Java family, JSP technology enables businesses to leverage Java language expertise, JavaBeans components, and existing Java technology-compatible components or data sources.