摘要：At first sight, Java's position as the de-facto standard for portable software distributed across the Internet seems virtually unassailable. Interestingly enough, however, it is surprisingly simple to provide alternatives to the Java platform, using the plug-in mechanism supported by the major commercial World Wide Web browsers. We are currently developing a comprehensive infrastructure for mobile software components. This is a long-term research activity whose primary objectives are not directly related to today's World Wide Web, but which targets future high-performance component-software systems. However, purely as a technology demonstration, we have recently started a small spin-off project called "Juice" with the intent of extending our experimental mobile-code platform into the realm of the commercial Internet. Juice is implemented in the form of a browser plug-in that generates native code on-the-fly. Although our software distribution format and run-time architecture are fundamentally different from Java s, and arguably more advanced, once that the appropriate Juice plug-in has been installed on a Windows PC or a Macintosh computer, end-users can no longer distinguish between applets that are based on Java and those that are based on Juice. The two kinds of applets can even coexist on the same Web-page. This, however, means that Java can in principle be complemented by alternative technologies (or even gradually be displaced by something better) with far fewer complications than most people seem to assume. As dynamic code generation technology matures further, it will become less important which code-distribution format has the largest "market share", many such formats can be supported concurrently. Future executable-content developers may well be able to choose from a wide range of platforms, probably including several dialects of Java itself. Hence, a pattern of "open standards" for mobile code is likely to eventually emerge, in spite of Java's current dominance.
关键词：Java; Juice; Oberon; Open standards; alternatives to Java; mobile code technologies; on-the-fly code generation; plug-in browser extensions
