Thursday November 02, 2006

Every developer for mobile devices faces the same problem: fragmentation of the Java ME market on the mobile phone handsets... The practice of creating an own version per each handset is not only costly and wasteful of resources - it is confusing to the end user. Additionally it inhibits the growth of the market for Java ME Platform.

Together Sun and Orange have worked to produce a set of guidelines for Java ME Platform programming that aim to reduce the practice of generating a distinct executable version (jar file) of an application for each and every phone. Last week, a joint paper has been announced and is now available at developers.sun.com. These guidelines look at some of the causes of fragmentation, and offer suggestions as to how an application may be written to achieve the optimal balance of application performance and coverage of a large number of phones.

Techniques for de-fragmentation
So, to use these guidelines, look at the capabilities that your application needs, for example screen output. Look at the guidelines for re-sizing images, determine what tolerances will work for your application, and apply the techniques to use one image to cover a range of varied screen sizes where the variation is relatively minor. The same can be done to cover different keypad inputs.

Generating one version to cover all phones is unlikely, but the fewer versions means a wider market and lower costs.

So to maximize the number of compatible devices per version, identify the platform and context that is relevant to the application. Then, for each point of variability, choose the technique to handle it. There is no general rule for selecting variability handling techniques, since some techniques may have different impact on different kind of applications.

More at developers.sun.com.