Java I/O, 2nd Edition

Chapter 24. The J2ME Generic Connection Framework

While Windows running on X86 processors still commands more than 90% of the desktop market and more than half of the server space, the embedded device market is far more diverse. The small device ecosystem contains hundreds of different processors and dozens of operating systems. To some extent this is a reflection of the diversity of the devices themselves. There’s not all that much difference between a laptop and a desktop and a blade server. They’re pretty much all rectangular boxes with the same basic hardware, give or take a couple of ports. By contrast, embedded devices cover everything from cell phones to PDAs to watches to car ignition systems to hotel door locks to televisions to jewelry—very different devices with very different needs. A CPU and operating system that work well for an iPod may be completely unsuitable for the hard real-time requirements of avionics controls. Still, even among similar devices such as cell phones, the market is far more diverse than it is in personal computers.

Java’s platform agnosticism makes it an obvious choice for the diverse embedded marketplace. It offers developers the hope of writing one piece of code that can run more or less reliably on many different vendors’ hardware. The fit is not always perfect, but it’s better than anything that has come before.

There are over two and a half billion Java-enabled devices on the planet today, and about 75% of those are embedded devices. These ...