1. Wireless Instant Messaging Using J2ME
Sreedhar Dasi
Vamshi Battini
Pradeep Gummi

2. OBJECTIVE Develop a wireless Instant Messaging application using J2ME
Provide an insight on J2ME and its importance in developing wireless applications.

3. About WIM
The application consists of Clients on the J2ME application and a server that handles all data storage,and communications between clients
Features of WIM:
Simple registration of new accounts (username, password) .
Authenticated user logon
Adding/Deleting buddy list members
Sending and receiving real-time messages

4. Possible Technologies:
WAP
Imode
J2ME

5. Java Micro Edition (J2ME)
J2ME is an optimized Java platform targeted at new generation applications for consumer electronics and embedded devices such as mobile phones,PDAs.
It’s Design Goals:
Device-specific APIs built on a common base
Aimed at devices with limited computation capabilities
Support wide variation of network connectivity
Ability to deploy applications to a variety of devices
A rich set of user interface and event handling class libraries that make the most of the limited display space.

6. Why J2ME for WIM? Platform Independency.
It provides rich set of user Interface and event handling libraries.
It provides rich set of network libraries that make network programming easier.

7. J2ME Architecture J2ME has a scaleable and modular architecture.
It defines 3 layers of software built upon a native operating system of a device.
Profile layer
MIDP PDAP Foundation
Profile
Configuration
CLDC CDC
Virtual Machine Layer
KVM CVM
Host operating System

8. Java Virtual Machine Layer
This layer is implementation of a Java virtual machine that is customized for a particular device’s operating system and supports a particular J2ME configuration
CVM:
It is fully featured JVM specially designed for high-end consumer devices.
It is an underlying virtual machine for (CDC).
It has a static foot print of 256 kb
KVM (K for kilo):
It is a small, yet very functional Java virtual machine specifically designed for resource constrained devices.
The current KVM has a static footprint in the range of 40 kb to 80 kb

9. Configurations
The Configurations define the Minimum Set of Java Virtual Machine Features and Class Libraries available on a particular category of devices.
Connected Limited Device Configuration (CLDC).
CLDC is the foundation of the Java runtime environment that targets small, resource-constrained devices.
The heart of CLDC is Sun's K virtual machine (KVM),
CLDC is suitable for devices with 16/32-bit RISC/CISC microprocessors/controllers, and with as little as 160 KB of total memory available .

10. Configurations contd. Configuration Device Configuration (CDC).
CDC configuration is for devices that are described as shared, fixed, connected information devices
Heart of CDC is C Virtual Machine
Memory budgets in the range of 128KB to 1MB.

11. PROFILES
Profile is a collection of application-oriented class libraries that address specific devices:
Personal Digital Assistant Profile:
It is a CLDC profile that provides user interface, persistence storage for small resource limited handheld devices as palm pilots.

12. Profiles contd MIDP Mobile Information Device Profile
It is a CLDC profile that provides the user interface, persistence storage, networking, and application model APIs for wireless devices.
MIDP addresses
Display toolkit, User input methods etc.
HTTP-based networking using CLDC Generic Connection framework
MIDP applications are known as “MIDlets”

13. J2ME Architecture for Wireless Applications
MIDP/CLDC/ KVM Architecture
MIDP Applications Device Specific Applications
Native
CLDC Classes Applications
KVM
Native System Software
MID Hardware
Device
Specific Classes
MIDP Classes

14. User Interface/MIDlet
WIM Architecture
Client Server
User Interface/MIDlet
SERVLETS
WIM Utilities
Connection
Services
Communication
Services
JDBC
MIDP
DATABASE
CLDC
KVM

15. Protocols implemented in MIDP
The MIDP specification requires all implementations to support HTTP.
HTTP can be implemented on the TCP/IP stack or WAP stack so long as it complies with the MIDP specification’s requirements for HTTP client connections.
MIDP specification requires protocol to be implemented using the J2ME Generic Connection Framework.

16. Generic Connection Framework
Networking and file I/O capabilities varies from one wireless device to another.
Ex: Packet switched networks and circuit switched networks
GCF is introduced in J2ME to reflect the requirements of small footprint networking for a broad range of mobile devices.
GCF defines the abstractions of the networking and file I/O so as to generally as possible to support the broad range of mobile devices.

17. Protocols implemented
HTTP protocol is implemented over the TCP/IP stack.

18. Demonstration of WIM