Dynamic Java Pages, Microsoft-Style

By RICHARD KARPINSKI

How's this for irony? Sun Microsystems is hoping to catch a ride on archrival Microsoft's coattails with a Java-based technology that mirrors Microsoft's popular Active Server Pages (ASP) platform.

Like ASP, Java Server Pages (JSP) let users embed code directly into HTML pages for server-side processing and the dynamic delivery of Web content--simplifying the mix of HTML, code and back-end objects.

Although ASP takes advantage of lightweight scripting languages like VBScript and JScript, JSP leverages the full Java programming lan guage. Likewise, while ASP links to back-office services and technologies including Microsoft's COM objects and Microsoft Transaction Server (MTS), JSP taps into Java servlets and Enterprise JavaBeans (EJBs) on the back end.

JSP was developed by Sun with major input from IBM. Public comment on the specification closed this month, and if no major objections arise, a 1.0 version could appear in the next few weeks, said Rob Clark, project leader for the Java Web Server at Sun.

"I really like ASP, and when I saw Sun moving in that direction, I felt very good about it," said Hugo Borda, chief architect at Claritas Corp., a user that is considering JSP as implemented in the latest release of WebLogic Inc.'s Tengah application server. "You'd use it for the same reason you use ASP--it makes it very easy to get at back-end [computing resources]."

"This has the promise to extend Java servlet functionality and make it much easier for us to build applications," said David Rae, systems architect at Norwest Mor tgage and a beta tester of IBM's WebSphere application server, which supports JSP.

"This is a very logical step," said analyst Tracy Corbo of the Business Research Group. "Everybody thinks you're going to jump right to EJBs. But servlets and JSP are good first steps."

Indeed, JSP, which was publicly disclosed for the first time at the JavaOne show last March, has been somewhat overshadowed by all the fervor over Enterprise JavaBeans, an architecture for building reusable Java objects.

Markup technology JHTML also has seized the spotlight. The more client-centric JHTML is similar to Dynamic HTML, but would let developers embed Java code, servlet tags and JavaBeans into HTML pages to enable client-side processing without a return trip to the server.

Both technologies, but particularly JSP, forward the important concept of clearly separating presentation and business logic in the creation of Web content, said Nigel Beck, program director of market management for IBM's WebSphere application server .

Webmasters and HTML writers can build Web pages and with JSP easily call out to prebuilt, Java-based code and objects, Beck said.

"We very much see sites being put together by two groups of people," Beck said. "The designer side needs an easy way to connect up to logic constructed by the more technical crowd."

Perhaps because of the rush to support EJBs, vendor pledges of support for JSP are somewhat mixed. Sun points to IBM, WebLogic, LiveSoftware Inc. and Sun's own Web server group as early deployers of JSP.

Some vendors said it was too new a technology to consider; others are sticking with proprietary technology.

JSP is best viewed as the next step in the evolution of Java servlets, Sun's Clark said. It builds on existing--but more limited--dynamic page compilation capabilities in earlier versions of Sun's Java Web Server technology.

JSP introduces new tags for embedding Java code in HTML pages, as well as a new <BEAN> tag to place objects directly on a page. When a page with a .JSP extension is requested, a JSP-based server creates and compiles a special servlet to dynamically generate the HTML content.

The advantage of JSP over ASP is that developers get the full power of the Java programming model, rather than more lightweight scripting languages, according to Clark.

In addition, ASP pages must be reinterpreted each time they are run, while JSP-generated servlets can be compiled once and run multiple times, he said.

Remaining Undaunted

Microsoft is undaunted. Not only is ASP a more mature technology--more than two years in deployment--but it benefits from other developments at Microsoft, such as the recent decision to meld COM+, MTS and Microsoft Message Queuing into a full enterprise middleware platform, said Michael Gross, platform marketing manager at Microsoft.

"As components behind ASP get stronger, so does ASP. COM and MTS are tremendous services, and ASP is an easy-to-use front end to get to them," Gross said.