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Sync up Palm OS with J2ME

Develop Palm HotSync conduits that interact with MIDP apps

By Jeb Beich, JavaWorld.com, 05/31/02

Have you used any standalone applications for your mobile device lately? Probably not; most applications would be useless without some communication to the outside world. For example, doctors and nurses now use their PDAs to obtain the latest medical information stored in databases residing on the Internet. Also, a variety of handheld devices offer real-time securities-trading software. In short, handheld devices provide a portable way to view information that changes day-to-day, hour-to-hour, or minute-to-minute.

Java 2 Platform, Micro Edition (J2ME) features all the tools developers need to create platform-independent applications for mobile devices. Its MIDP (Mobile Information Device Profile) technology lets you quickly and easily bring complex, form-based applications to market for a wide range of handhelds.

We typically categorize handheld devices by their accompanying operating systems. The major players include Pocket PC and Windows CE, from Microsoft, and Palm OS, from Palm. Palm OS generally runs on a significantly cheaper device, which could explain Palm's market dominance and success as a highly desirable platform for application development. The low cost of Palm OS-based devices make them an excellent choice for application distribution, where a buyer purchases a device solely for application use. A doctor, for example, might use a PDA not to manage his schedule, but to access the various medical databases available for handhelds.

The HotSync technology for Palm OS is an application installed with the desktop software distributed with every Palm OS-based handheld. Using a serial or USB (universal serial bus) cable, HotSync transfers applications and data through conduits that plug in to the HotSync Manager. HotSync has achieved an overwhelming degree of success. Conduits can be found in applications ranging from Intellisync for Yahoo!—which synchronizes personal information to your Yahoo Profile—to Delta Airlines' conduit, which allows users to obtain flight information over the Internet.

Many mobile applications rely on some form of communication with a central information system, possibly residing on the Internet. For many handheld applications, wireless is not an option, but HotSync might be. Palm's wireless Internet provider, Palm.Net, is still relatively expensive at 0 per month for unlimited access, and many users might find themselves without coverage if they stray from metropolitan areas. If their applications are Web-clipped or stream-based and depend on a connection, users might find themselves out of luck. HotSync allows users to transfer data stored on their PDAs at their convenience.

Having said that, however, I must also point out that HotSync does not fall into the MIDP specification and hence is not supported by Sun Microsystems. The question now arises whether implementing a MIDP application that relies on a HotSync conduit is sound. Have you defeated the point of using Java to create a platform-dependent application, when you could have used the native C libraries? Hardly: By developing a HotSync-based MIDP application, you save yourself a considerable amount of time and money, and leave open the possibility to decouple yourself from Palm OS at any time. For example, with MIDP, you can easily create GUI (graphical user interface) elements such as drop-down boxes. MIDP developers need not concern themselves with the diligent search for memory leaks, which can crop up in C development. In addition, the MIDP specification supports the standard HTTP protocol, which can replace the HotSync logic when a situation calls for it. You should take advantage of the HotSync technology, as you can easily develop and distribute a wireless solution later.

 

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