Java 2 Micro Edition: Professional Developer's Guide

The first book about Java 2 Micro Edition (J2ME), this book introduces you to J2ME programming. It includes discussions of the KVM small-footprint virtual machine, configurations, profiles, the Mobile Information Device Profile (MIDP), and some J2ME development environments and alternatives like Waba.

Published in late 2000, parts of this book are now dated. Still, it provides an interesting and comprehensive look at the issues that led to the development of J2ME and the general problems involved in making Java a feasible programming environment for handheld and other constrained devices.

Buy from Amazon.com

Summary

This book:

• discusses what Java 2 Micro Edition (J2ME) is and why it's needed;
• examines the configurations and profiles that make up J2ME;
• shows you how to use various J2ME implementations from Sun, Motorola and Research In Motion, as well as a discussion of Waba as an alternative.

Included with the book is a CD-ROM with code samples, the Motorola and Research In Motion SDKs, and additional material relevant to J2ME.

The reader is expected to know how to program with Java, but no experience with small computing devices is required.

Why I Wrote This Book

I wrote this book to provide Java programmers with an introduction and overview of what J2ME is and isn't, and how to go about writing applications for a J2ME-compliant platform. The book goes hand-in-hand with the various J2ME specifications, which of course are always changing and evolving.

Chapter-By-Chapter Descriptions

Here are detailed descriptions of each chapter:

   Introduction

Discusses why you'd want to (or not want to) use Java on small devices and introduces you to the rest of the book.
 

   Part 1: Java and Small Devices

The first part is a general discussion of Java and small devices.
 

1. It Really Is a Small World After All

Defines what small computing devices are all about.
 

2. Java: Fat and Slow?

Looks at the architecture of Java and its evolution so that we can better understand the need for something like J2ME.
 

3. Programming Strategies for Small Devices

Discusses design and coding strategies that you can use in order to write Java programs on small devices. Read chapter online (PDF).
 

   Part 2: J2ME Specifications

The second part defines what J2ME is and discusses the various specifications related to J2ME.
 

4. Java 2 Micro Edition (J2ME)

Introduces the Micro Edition and explains how it fits into the bigger Java picture. This chapter also traces the development of one of its key components, a new virtual machine called the KVM. Read chapter online (PDF).
 

5. Configurations

Describes the two initial J2ME configurations: the Connected Device Configuration (CDC) and the Connected Limited Device Configuration (CLDC). Configurations define basic Java language and runtime library support.
 

6. Profiles

Describes the first J2ME profile: the Mobile Information Device Profile (MIDP). This chapter also briefly describes other profiles that are currently in development. Profiles build on top of configurations by adding classes to support specific types of applications or uses of devices.
 

   Part 3: J2ME Implementations

The final part looks at actual J2ME implementations: how they work and how to use them.
 

7. The Connected Limited Device Configuration (CLDC) Reference Implementation

Shows you how to use the reference implementation of the CLDC on your desktop computer.
 

8. J2ME for Palm Connected Organizers

Shows you how to use the Palm operating system port of the CLDC reference implementation. This chapter includes a short discussion of the unique architecture of Palm devices and how to use and obtain the Palm OS Emulator so that you can try out the port even if you do not own a Palm device yourself.
 

9. The Mobile Information Device Profile (MIDP) Early Access Release

Shows you how to use the Early Access release of the MIDP reference implementation. This release includes a cellular phone simulator that lets you try your MIDP applications in a different environment than the Palm.
 

10. Java for Motorola Devices

Describes Motorola's implementation of the MIDP, the first complete MIDP implementation from a non-Sun party. A beta version of the Motorola J2ME SDK, complete with emulators for various Motorola cellular telephones, is available on the CD-ROM accompanying the book.
 

11. Java for BlackBerry Wireless Handhelds

Describes the BlackBerry Java Development Environment, another non-Sun J2ME implementation. An early access version of the BlackBerry JDE is available on the CD-ROM as well.
 

12. Waba: An Alternative to Java

Explores a similar but different take on making Java work on small computing devices.
 

13. Final Thoughts

Concludes the exploration with a few thoughts about the future of J2ME.
 

   Appendices

Two short appendices provide some additional information.
 

A. Tic-Tac-Toe Source Code

Source code to the simple tic-tac-toe game developed for the various implementations of J2ME.
 

B. CD-ROM Contents

Instructions on installing and using the CD-ROM.

For More Information

See my J2ME pages for more J2ME information.