Wizard API updated!
Tim Boudreau has released a new version of the Swing Wizard library (version 0.997) that fixes the WizardException bug reported in JavaWorld's recent Open Source Java Project profile. The article's examples have been reworked to test out the new, improved WizardException. Thanks, Tim, for this helpful fix!
Open Source Java Projects: The Wizard API

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WAP for Java developers

Develop WAP applications with Java servlets and JSP

By Qusay H. Mahmoud, JavaWorld.com, 06/02/00

Most Internet technologies have been designed for desktop and large computers running on reliable networks (with relatively high bandwidth). Handheld wireless devices, however, have a more constrained computing environment compared to desktop computers. Handheld devices tend to have less memory, less powerful CPUs, different input devices, and smaller displays. Further, wireless networks have less bandwidth and more latency compared to wired computer networks.

WAP, the Wireless Application Protocol, was designed to take advantage of the several data-handling approaches already in use. WAP integrates the Handheld Device Markup Language (HDML) and the Handheld Device Transport Protocol (HDTP) developed by Unwired Planet (now known as Phone.com), as well as Nokia's Smart Messaging Protocol (SMP), and Ericsson's Intelligent Terminal Transfer Protocol (ITTP). WAP services can be hosted on Web servers using technologies such as Java servlets and JavaServer Pages (JSP). In this article, I show you that WAP and Java are complementary, not competing, technologies. WAP is meant for cellular phones, and Java aims at more sophisticated network terminals.

The WAP platform is an open specification that addresses wireless network characteristics by adapting existing network technologies (and introducing new ones where appropriate) to the special requirements of handheld wireless devices. Therefore, WAP intends to standardize the way wireless devices (mobile phones, PDAs, and so forth) access Internet data and services. WAP's reuse of existing Internet protocols will ease the development of WAP services for Java and other Web developers.

To facilitate the delivery of Internet data to wireless devices will certainly lead to the introduction of new technology. For example, wireless devices have small screens compared to desktop computers, and therefore HTML (which is visually rich) is not appropriate for small screens. The small screen and the computing power, which is increasing, represent a limiting factor in running complicated Java applications with intensive graphics. However, efforts are being made for having a compact subset of the Java language suitable for mobile applications. In this article, you learn how to develop WAP applications using Java servlets and Java Server Pages.

But first, I describe the WAP platform and how it incorporates several technologies that are similar to existing ones but that have been designed specifically for wireless devices.

The WAP architecture

The WAP standard defines two essential elements: an end-to-end application protocol and an application environment based on a browser. The application protocol is a communication protocol stack that is embedded in each WAP-enabled wireless device (also known as the user agent). The server side implements the other end of the protocol, which is capable of communicating with any WAP client. The server side is known as a WAP gateway and routes requests from the client to an HTTP (or Web) server. The WAP gateway can be located either in a telecom network or in a computer network (an ISP). Figure 1 illustrates an example structure of a WAP network.

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