Road to Java Can Take Different Paths

[Editor’s Note: This article is the third and final installment of a series of articles on making the transition from RPG to Java in an AS/400 shop. The first two parts of this Road to Java series dealt with migrating from RPG III and CL to RPG IV and ILE CL, then embracing modular ILE programming. This article will discuss the options available for developing Java applications on the AS/400.]

You’ve made the jump from RPG III and CL to RPG IV and ILE CL. You’re starting to see the benefits of modular ILE programming in your environment. You’re ready to see what Java can do for your AS/400 applications.

But you still have a huge investment in RPG in terms of code and skills so you’re not sure at what level you want to embrace Java. Fortunately, AS/400 shops have a number of options when it comes to introducing Java into their environments, ranging from simple screen-scrapers to create Java client GUIs to Web application servers that “bridge” RPG applications to Java, all the way up to full-scale Java development.

“Do you just need a graphical interface or do you need to get your applications out on the Web?,” asks John Quarantello, AS/400 Java marketing manager at IBM. “You can use a screen-scraper and leave your back end untouched or use a product like Lansa or Sterling to extend your business logic out to the Web, or you can write your own Java code. There’s many ways to take the next step. It depends on your budgets and timeframes.”

Jim Anderson, Java manager for IBM AS/400 Partners in Development, describes four different “investment areas” for customers looking to add Java to their environments.

The first investment area is simply converting RPG greenscreens to a Java GUI front end, which can allow companies to take advantage of a browser-based interface. This is commonly known as screen scraping. The second maintains the RPG back end, but connects the back-end business logic to a Java-based middle tier or application server.

The third area, discussed in previous articles, involves modernizing your RPG code to co-exist with Java. And the fourth investment area calls for full-blown Java development, so you can integrate your applications with other applications or business systems on other platforms in your enterprise.

Of those, IBM sees the Web application servers as being a good Java fit for many AS/400 users. IBM’s WebSphere Java application server became available for the AS/400 with V4R3 and will support Enterprise JavaBeans by the fourth quarter of this year [though a product preview of EJB-based WebSphere is available now]. Meanwhile companies like BEA [formerly WebLogic], Bluestone and Novera already support EJB application server technology for the AS/400.

“You introduce new applications into the application server tier, but keep your RPG investments because they use the same business rules as your RPG applications on the back end,” says Anderson. “It’s also a way to manage your skill transition. You keep your RPG guys and hire new developers for the middle-tier applications.”

Anderson says the RPG developers can “mentor” the Java developers since the middle-tier Java applications will use the same business logic as the back-end RPG applications.

“For the majority of the RPG crowd, this is one of the environments for the future. They can extend their applications to the Web, into an extranet or intranet environment for business-to-business e-commerce,” Anderson says.

“Do they feel pressured to modernize their applications and get on a cost-effective platform that’s more open? Then this is a solution for them. If you’re happy where you are, then stay there as long as you can. Don’t move to Java until you’re ready.”

“If you just want a modern graphical user interface, then you’re talking about a screen-scraper,” says Quarantello. “If you want to re-engineer code and get into building component technology and distributed objects, then you can do it with JBuilder or VisualAge [for Java] for industrial strength applications or a 4GL tool like Lansa or Sterling [COOL:Plex].”

Anderson says he doesn’t place much stock in screen scraping, which he describes as a “short-lived investment.” But he recommends that AS/400 shops start small with an eye towards working their way up, gradually building their skills as the technology matures.

“I’m very bullish on Java on the AS/400. We have a very robust Java environment that’s ready for deployment of mission-critical applications. The technology is built as well as on any platform and as the technology gets better and better, we’ll be on the vanguard of it.”