This document outlines an agenda for a J2ME mobile app development workshop. It includes sections on programming for mobile devices, Java and mobile app development, the J2ME architecture, how to write code and scope, test, and deploy J2ME apps. It also discusses tools, best practices, and includes a networking demo. The goal is to educate attendees on developing apps for mobile Java platforms like J2ME.

1. J2ME MOBILE APP
DEVELOPMENT
ON-STAGE WORKSHOP
Krishna Engineering College, Coimbatore

2. Agenda
 Programming for Mobile Devices
 Java and Mobile Application Development
 J2ME – Architecture
 How to write Scope for J2ME app
 How to write code for J2ME app
 How to Test J2ME app
 How to Deploy J2ME app
 Utilities and Tools
 Community Best Practices
 Demos
 Discussions

3. Programming for Mobile
Devices
 Advantages
 Mobile is next-gen computing device [smart-phone,
PDA]
 Design, Development, Testing Opportunities [Web /
App]
 Wide Range of Applications required
 Edutainment, Infotainment, business, communication,
social networking … 1000 more…
 Limitations
 Small Size and Low power Handsets
 Operating Systems, Screen Size, Memory, Processor,
Network, Input Methods and Graphics Engine

4. Java and Mobile App
Development
 Opportunities: C++, .NET, Flash-Lite, Java, HTML/JS/PHP, Python
 Java – Independent from Hardware Platform
 Byte Code - Compiler and Code Interpreter
 JVM, KVM [128K of available memory], Card VM
 KVM – C based. Responsible for Byte code to Native calls
 Java for Mobile Operating Systems – J2ME
 Business applications, Games, Mobile Utilities, Location based
Services, Social Media, Communication Tools etc…
 Operating Systems
 Symbian [Feature Phone / Smart Phone]
 Blackberry
 Android
 Windows Mobile
 I-Phone
 Common Java Phones

5. J2ME Market Trends
 900 million mobile Java devices shipped by
2010
 1235 Mobile Java Device Models in Market
 95 Mobile Device vendors using Java
 90000 Mobile Java Applications in Market
 260 Operators worldwide developed java
services
 23 million mobile java downloads every month
 Source– Nokia News, Mobile Today, Symbian
News, Oracle Java Networks

6. J2ME Packages
 Javax.microedition
 Multimedia Supplements
 Content Handlers
 Web Services
 Location based API
 3D Graphics
 Mobile Sensors
 Payment API
 Security
 Wireless Messaging
 XML

7. Limited K-Virtual Machine
Support
 No Floating point Support
 No JNI
 No Thread Groups and Daemon Threads
 Sand box Security

8. J2ME Keywords
 CDC – Connected Device Configuration
[handheld PCs, Smart Devices, Televisions]
 CLDC – Connected Limited Device Configuration
[Mobile Phones, Smart Phones]
 CLDC 1.0
 CLDC 1.1
 Device Profile – MIDP [Mobile Information Device
Profile]
 MIDP 1.0
 MIDP 2.0
 MIDP 2.1

9. Connected Limited Device
Configuration
 CLDC provides the lowest common denominator
for small and resource-constrained devices
 characterized as follows:
 160 kB to 512 kB of totally memory budget available
for the Java platform.
 a 16-bit or 32-bit processor.
 low power consumption, often operating with battery
power.
 connectivity to some kind of network, often with a
wireless connection and with limited (often 9600 bps
or less) bandwidth.

10. MIDP
 MIDP adds an additional layer on the top of
the CLDC providing APIs for a specific class of
devices:
– 128KB of non-volatile memory for the MIDP
implementation
 – 32KB of volatile memory for the runtime heap
 – 8KB of non-volatile memory for persistent data
 – Input capacity (screen, keyboard, touch)
 – Screen size of at least 96x54 pixels

11. Midlets – J2ME Apps
 MIDlet defines methods that the system calls
in order to start, stop (pause), and destroy the
application
 classes to build user interfaces
 Storing data in simple databases [RMS]
 Network Connectivity
 Timer notifications
 .jad and .jar files

12. J2ME – Architecture

13. J2ME - Architecture
Operating System

14. AMS and Midlets
 • The Application Management Software
(AMS) manages the MIDlets.
 • The AMS is a part of the device's operating
environment and guides the MIDlets through
their various states during the execution
process.

15. Structure of MIDP Code
 J2ME SDK 3.0 – Tool Introduction
 Code Example – First J2ME Midlet

16. How to write Scope for J2ME
 Understand the requirement from the mobile
device point of view
 Understand the limitations of device and
network
 Structure of Scope document
 Scope in User case / Story
 Functional Requirements + Functional Flow
 Target Devices + Platform + User Knowledge
 Constraints and Limitations

17. How to write code for J2ME
 Code Sample – Midlet with UI & Fetch System
Properties
 Code Best Practices
 Clean Code
 Follow the Coding Standards – Documentation
 Exception Handling
 Use descriptive variable names
 Don’t Copy-Paste. Use functions
 Use the default structure in Editor
 Understand the Project Properties

18. How to Test J2ME Midlet
 Rule 1: Plan your devices
 Rule 2: Always do Unit Testing in Emulators
 Rule 3: Use real-time Devices for Test cases
verification
 Rule 4: Certify your Midlet
 Rule 5: Sign Midlet for Security reasons

19. How to Deploy J2ME Midlet
 Jad [app-descriptor] and Jar[java-archive]
Files
 Bluetooth & USB
 Public App-Store [getjar.com]
 Branded App-Stores [Symbian Store]

20. Utilities and Tools
 J2ME PLATFORM SDK 3.0
 Borland JBuilder 7 Enterprise with MobileSet 3
 Sun Microsystems' Sun ONE (Open Network
Environment) Studio 4 Mobile Edition
 Metrowerks CodeWarrior Wireless Studio 7
 S5 Systems' jVise (based on IBM Eclipse
technology
 Emulators [J2ME] – Online and PC Based
 UI Design Tools [Prototype and Form Design]

21. Community Best Practices
 Create new requirements and develop apps
 Follow user story + build level scope + clean
code
 Write algorithm before coding
 Do more in Server, Less in Device
 Try simple UI
 Define Target Devices in release notes
 Share Knowledge & Experiences

22. Networking with J2ME Demo
 Networking – Reading from Remote
 Code Sample

23. Discussions…
muthugv@ovi.com
9894238404
http://office.gvmuthu.com
http://twitter.com/#!/gvmuthu