Foreword Foreword It started as wild idea, emerged as a standard, and grew into a phenomenon. Applications that go with you, whenever and wherever you are, and the infrastructure that lets you find them, buy them, and use them. With hundreds of millions of mobile Java-capable devices out there, the potential for developers is really amazing, and because the market is still young, there is still lots of room for innovative applications. There is still plenty of opportunity to get in on the "ground floor" of this industry and then ride the wave... to the top. Ever since we first developed the DoCoMo Java architecture that started it all, people have been asking me "what is the killer application for mobile Java?" My answer has stayed pretty much the same... it is the application right now that solves a need that a user has right now ! So what do users want? What will they pay for? How do you learn how to build it? And who do you partner with? The answers are here in this book, in readable, practical form. So what will you build? To date we have seen a tremendous growth in the availability of high quality, entertainment-focused applications for the mobile marketplace. These applications have been very successful in delivering a good experience to the user even though they have not tried to create an online- or community-based entertainment experience. Using MIDP 2.0, the next generation of applications can take advantage of the capability of the newer mobile devices to connect to both other local devices and the wider service network. This will enhance existing types of entertainment applications and facilitate the creation of new communication and community applications that are interesting for both the consumer and the business user. Who do you partner with? Nokia developer platforms offer the highest volume opportunity for mobile developers, with an installed base measured in the hundreds of millions. Series 40 Developer Platform offers the highest volume opportunity in the family, and offers a robust technical platform including secure communications, mobile media, messaging, graphics, and Bluetooth. (MIDP 2.0, JSR 120, JSR 135, JSR 82). How do you build it? Developing Scalable Series 40 Applications is an end-to-end solutions guide for Java programmers focusing on Nokia s Series 40 Developer Platform. It brings together two of the largest segments of the mobile marketplace, Nokia Series 40 handsets and the worldwide mobile Java developer community, and provides thorough and specific information on how to create scalable mobile applications. These applications will work on the newest Series 40 handsets (based on MIDP 2.0), serve the large installed base of MIDP 1.0 handsets, and scale up to serve owners of smartphones based on Series 60 Developer Platform, enterprise communicators based on Series 80 Developer Platform, and rich media devices based on Series 90 Developer Platform. Developing Scalable Series 40 Applications details the technical underpinnings of the Series 40 Developer Platform. It includes not only the available APIs but also coding best practices, architectural considerations, and fully tested sample applications ready for download. The book includes plenty of specific tips; for example, pointing out the choices Nokia made when implementing optional APIs. The book goes beyond presentation of methods and classes. Mobile devices serve a variety of highly specialized customer segments, and some differentiation among devices is necessary to create the high-volume opportunity developers can now tap. Additional differentiation occurs as new devices add features on top of existing feature sets. To serve the mobile mass market at a profit, the right technical approach is critical to avoid fragmenting an application s code base. This book addresses development approaches that allow applications to scale across devices and time. The authors devote a full chapter to code management, sharing tips on how to optimize the mobile experience for a variety of users without fragmenting the code base. The authors and Nokia are uniquely positioned to guide developers through the process of profitable end-to-end Java application development. Nokia has offerings at all levels: clients (Series 40 through Series 60, 80 and 90); servers (SMSC, MMSC, Nokia Mobile Services SDK); and technology leadership, including the specification leadership of a number of JSRs involving communication, UI, mobile management, and architecture. Author Michael Juntao Yuan is a developer and software architect for open-source mobile software. Kevin Sharp is a consultant, and professional engineer specializing in mobile logistics and supply chain infrastructure. Both authors are frequent contributors to Forum Nokia and have had extensive access to and support from Nokia software designers, technical architects, tools developers, and technical support teams throughout the company. Developing Scalable Series 40 Applications steps the Java developer through the process of end-to-end application development for today s highest volume mobile platform. It includes lots of code and examples, plus 11 end-to-end projects including client-side source code, server code, and tips on how to scale the client side to encompass other device families including Series 60 Developer Platform. Every code sample has been tested and is available for download. Developers can just load a sample and get started on projects of their own. I have had the good fortune to be involved with mobile Java from the very beginning and I know what it takes to be successful in this marketplace. I believe that this book can really help you be successful with mobile Java application design and development. If you take the information in this book and sprinkle it with some imaginative application ideas, I think you will have a winning combination. I have seen from the inside how committed Nokia is to make a successful developer community, and I think that passion shows in this book and the other resources available from Forum Nokia. Go fast... Go mobile. Jon Bostrom, Sr. Director, CTO Java Technology Platforms, Nokia Copyright Pearson Education. All rights reserved.