The use of Java to build application servers is gaining in popularity and is in fact dominating that market. Two leading vendors in this realm, BEA Systems and iPlanet, have been certified for the Java 2 Enterprise Edition (J2EE) platform specification from Sun Microsystems. IBM is likely to follow suit.
Driving the greater acceptance of J2EE-based application servers is the promise that they can be interchangeable, no matter the vendor.
Sun's goal for J2EE, now in Version 1.2, is to create an environment in which customers can write to the J2EE specification and in which any application created will work across any J2EE-compatible application server. "The write-once, run-anywhere portability of Java has been delivered to the server," says Rick Saletta, group marketing manager for J2EE at Sun.
Although based on an open standard, Java-based servers need to conform to Sun's J2EE specifications. In order to be certified, vendors' J2EE application servers have to pass a series of compliance tests. Of the 25 J2EE licensees, nine have already received certification, and the others are working toward it, says Milena Volkova, Sun's J2EE product marketing manager.
"Customers are much more interested in J2EE now than they were six to nine months ago," says Mike Gilpin, vice president and research leader at analyst Giga Information Group.
Analyst firms agree that BEA and IBM are the top two players in the application server space; iPlanet currently holds the third spot. IBM, an important backer of Java, is not currently certified for J2EE 1.2 but is working to pass the more than 6000 tests.
Using the J2EE platform, companies can build Web stacks on a standard application server without having to make a huge platform choice and then be stuck with it. Users can switch application servers if they discover the need for a proprietary feature of another product.
"It's entirely possible that, if a customer went down one path and changed their mind, it would be feasible to switch servers," says Jim Rice, a technical architect at Luminant Worldwide, an e-business services company, in Dallas.
But that is not to say that the process would be a cinch. If one vendor has any proprietary code, for instance, that would lead to porting issues. Rice says that applications written for a server from one vendor should also be able to access data from another vendor's application server.
Luminant uses primarily SilverStream application servers, Rice says, allowing it to access the Enterprise JavaBeans (EJBs) of other vendors' products. The EJB is both a comprehensive programming model for components and a vendor-independent programming interface standard for Java-based servers.
The proliferation of J2EE-compliant application servers leads to other advantages that are not as prevalent for proprietary application servers, such as the capability of easily reallocating developer personnel resources and reusing code components.