Write once, run anywhere: An impractical idea
T he long-running debate about whether Java or ActiveX will dominate HTML-based Web application development has come to a halt. Java won.
But the victory hasn't brought Java's "write-once, run-anywhere" philosophy any closer to reality. Ask almost any consultant, programmer or independent software vendor, and they will laugh off the notion of write once, run anywhere as an unattainable ideal.
How can this be? Of course we all know how the Java world has Balkanized into increasingly centrifugal camps around Sun, Netscape, Microsoft, Hewlett-Packard and other players. All pledge nominal fealty to the notion of a single set of Java standards.
Yet the fact that no two Java software vendors offer the same set of templates, beans, classes, methods or other development features means that write once, run anywhere, if possible at all, must be addressed through painstaking application planning, design and testing. It cannot be taken for granted.
Another probably more fundamental factor often is overlooked in discussions of cross-platform application development: Java, for all its burgeoning diversity, is only one detail in a complex canvas. Often the best you can do, given limited time and development resources, is optimize an application for a particular target client environment and pray that pages display and components execute reasonably well in other environments.
So you choose an HTML version, a leading Java integrated development environment (IDE) and a target Java virtual machine (JVM), usually the one in Microsoft's Internet Explorer 4.0 or Netscape's Communicator. You also concentrate on application development at the server, not client, level. The World Wide Web or application server does the heavy processing and delivers plain old HTML and GIF documents to thin clients.
What gets lost in this emphasis on cross-platform Web applications is any hope of wowing users with state-of-the-art interactive and multimedia features. You can reach more potential browsers by delivering plain-vanilla, boring, static pages or impress a select few by sending them the latest widgets, bells and whistles.
Or if you're a glutton for punishment and want to make a go of write once, run anywhere without sacrificing state of the art, you can drag yourself through the following drill.
First, write complex, potentially buggy Web template applications that deliver pages and components that display and execute approximately the same way across various platforms.
Test these applications in all potential browser, client and operating environments before going live. Upgrade the applications continually to incorporate any hot new JVM, just-in-time compiler, browser, markup, component, scripting and database technologies.
Even then, these applications are not truly write once, run anywhere unless they can be compiled and run acceptably on all native platforms. Here's where ActiveX comes back into the picture.
Yes, ActiveX is dead on the Web, but it remains very much alive on the desktop. To the extent that application developers are still writing native applications directly for the Windows environment and not to a browser running under this or any other operating system, ActiveX will remain a strong rival to Java, keeping the latter from achieving the universality its proponents desire.
Most levelheaded IT professionals know that Java-based network computers will not replace or obsolete Windows on the mainstream corporate desktop. By the same token, ActiveX will not stray far beyond its Windows origins to do serious battle with Java in cross-platform computing.
Blurring the boundaries between Java and ActiveX, an increasing number of IDEs let you compile Java code directly to native Windows, and Microsoft has a binding that lets you write ActiveX controls in Java. But what we're looking at here is another serious engineering effort by overworked programmers to support cross-platform applications in a world that still doesn't revolve around Java or the Web.
Nevertheless, ActiveX is clearly on the defensive. For the time being, it will rely on its superior native platform integration to retain the upper hand over Java applications. However, incorporation of a fast JVM into Windows 98 will tip the cross- platform balance in Java's favor. Likewise, Microsoft's decision to emphasize Dynamic HTML for compelling content development is another sign that ActiveX is on the endangered species list.
This proliferation of competing Web application development technologies has doomed write once, run anywhere to the dustbin of yesterday's ideals. It will not be a practical application development strategy until the Java industry shakes out into one rigorously standardized community and Microsoft totally rearchitects Windows around Java.
In other words, don't get your hopes up.
