David Hemphill

As J2ME gains prominence, the range of things that developers can do with Java on devices is expanding. This month I’ll cover the Mobile Media API (JSR-135), which is an optional J2ME package. The Mobile Media APIs enable the playing and recording of audio, taking pictures and playing videos, and other things.

Wireless technology is evolving at a rapid pace. There is a lot of talk about mobile and wireless computing and there is also a fair amount of hype. However, the one thing that is conspicuously absent from much of these discussions on mobile and wireless computing is a discussion on what these devices are connecting to. The fact is, most of the value, in terms of content and capabilities of the device, is a result of interacting with a server of some type. This is true whether we are talking about microbrowsers such as WAP and iMode, J2ME clients, or short message service (SMS) and email. Behind the scenes these devices are interacting with services that reside somewhere on a network. These services handle much of the complex details of the features offered by wireless devices. Although there are complexities that the mobile device must deal with, a well-designed wireless architecture delegates as much complexity as possible to the server. This is desirable because servers have more processing capabilities and do not have the power restrictions of mobile devices (i.e., servers don’t run on batteries that are worn down by the CPU). This article examines wireless computing from the server’s perspective. First, the problems of wireless computing or the public Internet are discussed. Then various models that help address these problems are provided.