J2ME is a Java platform for mobile and embedded devices. It includes configurations like CLDC for small devices and profiles like MIDP for mobile information devices. J2ME provides advantages like cross-platform development, robustness through virtual machines, security features, and connectivity to Java enterprise applications. It allows developing applications for a wide range of devices from set-top boxes to phones using a single Java codebase.

1. Java 2 Micro Edition
Introduction
Cornelius Koo - 2005

2. What is J2ME
• J2ME is a development and runtime
environment designed to put Java
software on consumer electronics and
embedded devices.

3. What is Mobile Devices
• Those computing devices that easily
carried and used while in transport.

4. What is Wireless Device
• Device capable of communicating or
networking without wire or cable.

5. Micro Devices

6. History
• Before Java was called Java, it was Oak–
a programming language designed for TV
set-top boxes and other devices.
• J2ME come at last (1999), after J2SE and
J2EE, targeting “information appliances”
ranging from Internet enabled TV set-top
boxes to cellular phones.

7. Advantages of Java Technology
• Cross platform: This is very important in
the diversified mobile device market. In a
heterogeneous enterprise environment,
the ability to develop and maintain a single
client for all devices results in huge
savings.

8. Advantages of Java Technology
• Robust: Since Java applications are
completely managed, the bytecode is
verified before execution, and memory
leaks are reclaimed by garbage collectors.
Even if a Java application does crash, it is
contained within the virtual machine. It will
not affect other sensitive applications or
data on the device.

9. Advantages of Java Technology
• Secure: The Java runtime provides
advanced security features through a
domain-based security manager and
standard security APIs.

10. Advantages of Java Technology
• Object oriented: The Java language is a
well-designed, object-oriented language
with vast library support. There is a vast
pool of existing Java developers.

11. Advantages of Java Technology
• Wide adoption at the back end: It is
relatively easy to make Java clients work
with Java application servers and
messaging servers. Due to the wide
adoption of Java 2 Enterprise Edition
(J2EE) on the server side, mobile Java is
the leading candidate for enterprise
frontend applications.

12. Java Family
• Standard Edition (J2SE)
Designed to run on desktop and workstation
computers
• Enterprise Edition (J2EE)
With built-in support for Servlets, JSP, and XML,
this edition is aimed at server-based applications
• Micro Edition (J2ME)
Designed for devices with limited memory
display and processing power

13. Java Family

14. J2ME Platform

15. Configuration
• Configuration defines a Java Platform for a
broad range of devices.
• Configuration defines the Java language
features and the core Java libraries of the
JVM for that particular Configuration

16. Connected Device Configuration
(CDC)
• 512 kb (minimum) memory for running
Java
• 256 kb for runtime memory allocation
• Network connectivity, possibly persistent
and high bandwidth

17. Connected, Limited Device
Configuration (CLDC)
• 128 kb memory for running Java
• 32 kb memory for runtime memory
allocation
• Restricted user interface
• Low power, typically battery powered
• Network connectivity, typically wireless,
with low bandwith and intermittent access

18. Profile
• Profile is an extension to Configuration.
• It provides the libraries for a developer to
write applications for a particular type of
device.

19. Profiles

20. Profiles Hierarchy

21. MIDP
• Mobile Information Device Profile defines
APIs for user interface components, input
and event handling, persistent storage,
networking and timers,taking into
consideration the screen and memory
limitations of mobile devices.

22. Compact Virtual Machine (CVM)
• Has approximately the same spec as
J2SE.
• Supports for Java 2 v1.3 VM features and
libraries : Security, Weak References,
Java Native Interface, Remote Method
Invocation, Java VM Debugging Interface.

23. Kilobyte Virtual Machine (KVM)
• Requires only 40 and 80 kb of memory
• Only 20-40 kb of dynamic memory (heap)
required
• Can run on 16-bit processors clocked at
only 25 MHz

24. MIDP Architecture

25. J2ME Executive Committee

26. Reference
• Core J2ME Technology and MIDP. John
W. Muchow. Prentice Hall PTR, 2002.
• Enterprise J2ME: Developing Mobile
Java Applications. Michael Juntao Yuan.
Prentice Hall PTR, 2003.
• J2ME in A Nutshell. Kim Topley. Oreilly,
2002.