Java Server Page

Sun's standard practice for a Java API is to provide the API specification with documentation and a reference implementation, so developers and companies can refer to a code implementation as they develop their own. Sun provides the following deliverables for JSP technology:

The JSP Specification - This document defines the application programming interface. The specification is a useful source document for JSP syntax.
The JSP Reference Implementation - Sun licensed the JSP and Servlet Reference Implementation to the Apache Software Foundation. This project, called Tomcat@Jakarta , is freely distributable and licensed directly from Apache. Tomcat is already pre-integrated with the Apache Web Server, a popular Web server. For those not using the Apache Web Server, most other Web servers are well on their way to shipping support for JSP technology (see java.sun.com/products/jsp/ for more information).

To understand how JSP technology fits in the progression of products supporting dynamic content, it is worth describing a few of the alternatives.

CGI (Common Gateway Interface) - CGI programs were an early solution for simplifying dynamic content. CGI programs are typically written in C or in Perl, a freely-distributed programming language. Still prevalent in Web-based applications, they can experience severe performance problems when scaling to support high-volume access.
Mod_perl is a plug-in for the Apache Web Server that integrates the Perl programming language with the Web server, so programmers can write Web server extensions in Perl. As a replacement for the CGI interface, mod_perl addresses some of the limitations of CGI. This is a powerful solution, but it still has the programmers developing the pages themselves, and is tied closely to the Apache Web Server.
Microsoft Active Server Pages (ASP) technology is closer in spirit to JSP technology than the others because its goal is to simplify the page development process. ASP is essentially limited to the Microsoft IIS Web Server information, see java.sun.com/products/jsp/ .) ASP relies heavily on Basic-based scripting languages, which tend to be less scalable and more difficult to maintain over time than a component -based approach.