Petr Panteleyev's Blog

J2ME Archives

Java ME Optional Packages in Y2007

There were some highlights regarding optional packages last year that I'd like to talk about a bit.

1. We've delivered as many as 14 optional packages as part of Sun Java Wireless Client 2.0.

2. We've made a huge work on refactoring almost all our existing optional packages to meet new CDC world. Now our optional packages implementations are ready for both CLDC and CDC deployments.

3. We've unified implementations for real devices and emulation. So, developing mobile applications with NetBeans Mobility you have the same stack as on a device. Big part of this work was to propagate a native porting layer called JavaCall™ to all our implementations.

4. We continued to implement new optional packages. Some of them will be available with the next SJWC release.

What I would say for year 2008? Java ME is far from being dead. We have many new JSRs to implement and deploy. There is a big demand from carriers and vendors. Stay tuned.

Java ME on Windows Mobile

Many people keep asking about Java ME on Windows Mobile.

Well, phoneME Advanced should become an answer in some time. However, here are some brief instructions how to get Java ME (CDC) on Windows Mobile right now.

First, look at phoneME Advanced Wiki. There are lots of pages regarding CDC on various platforms. Windows Mobile is one of them.

Then, look at Windows Mobile build instructions.

CDC and core packages should work without any additional efforts.

Optional packages are more tricky. Although Windows Mobile provides unified API among devices, each device introduces specific issues related to the hardware. There are different Bluetooth stacks, various multimedia codecs and filters may be included or excluded by vendor. This means that optional packages like JSR 135 or JSR 82 must be ported to a particular device of your interest.

Optional Packages in phoneME Advanced

Optional package is a set of technology-specific APIs. It's called 'optional' because a particular device may not support some technology and thus the corresponding API is not provided by Java ME on that device.

Historically, almost all existing Java ME optional packages were developed with MIDP and CLDC in mind. So, all of them depend on MIDP API and have MIDP centric architecture. This way they are present now in the phoneME Feature code base.

At the same time there is phoneME Advanced project. It has CDC based architecture targeting advanced phone segment of the market. CDC world provide much more API-rich profiles and also introduces several application models like Xlet and 'main'.

We are targeting two primary goals:

• Utilize all new powerful features of "advanced phone" devices.
• Facilitate smooth transition of the existing application base between "feature phone" and "advanced phone" devices.

To make those goals achievable we are now working on the new architecture for the optional packages with the following requirements:

1. Architecture should be unified between different platforms, application models and device types:
   • phoneME Feature / phomeME Advanced
   • MIDlet/Xlet
   • real device / emulation
2. Code reuse between different implementation should be as much as possible
3. Specific parts of the implementation should be optimized for the corresponding platform.

In this blog I plan to cover various aspects of this new architecture and our progress with optional packages.

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