What is J2ME?Java2 Micro Edition Java Platform, Micro Edition, or J2ME, is a Java platform designed for embedded systems (mobile devices are one kind of such systems). Devices such as: Mobile Phones Pagers PDA’s Car Navigation Systems Internet Appliances Set-Top Boxes
The J2ME Universe PDAP Personal Profile MIDP Personal Mobile Information Personal Basis Profile Digitial Assistant Device Profile Profile Foundation Profile CLDC CDC Connected, Limited Device Configuration Connected Device Configuration J2ME Java 2, Micro Edition
J2ME Profiles The Connected Limited Device Configuration (CLDC) Contains a strict subset of the Java-class libraries, and is the minimum amount needed for a Java virtual machine to operate. CLDC is basically used for classifying innumerable devices into a fixed configuration. Mobile Information Device Profile (MIDP) - Designed for mobile phones Information Module Profile (IMP) - is a profile for embedded, "headless" devices such as vending machines, industrial embedded applications, security systems, and similar devices with either simple or no display and with some limited network connectivity.
J2ME Profiles Connected Device Configuration (CDC) The Connected Device Configuration is a subset of Java SE, containing almost all the libraries that are not GUI related. It is richer than CLDC. Foundation Profile - This profile is intended to be used by devices requiring a complete implementation of the Java virtual machine up to and including the entire Java Platform, Standard Edition API. Personal Basis Profile - The Personal Basis Profile extends the Foundation Profile to include lightweight GUI support in the form of an AWT subset.
MIDPMobile InformationDeviceProfile Java ME devices implement a profile. The most common of these are the Mobile Information Device Profile aimed at mobile devices, such as cell phones, and the Personal Profile aimed at consumer products and embedded devices like set-top boxes and PDAs.
MIDP vs J2SE No Native Methods Threading, but no use of interrupt() No file-based I/O Many classes with fewer methods Collections (Vector, Hashtable & Stack)
What makes up a MIDPApplicationMIDP Applications are composed of twoprinciple partsJAR File – Contains all of the classes andresources used by the applicationJAD File – Application descriptor,describes how to run the MIDP application
JAD Files Very simple NON-XML config file Application Name MIDI version Copyright and version information Location of the JAR file
Getting StartedWhat do I need? J2SE (http://sun.java.com) Sun’s J2ME Wireless Toolkit (http://java.sun.com/products/j2mewtoolkit/) Internet Connection Publicly accessible website or public static IP address
References Sun Microsystems J2ME http://java.sun.com/j2me/ Deploy your J2ME Application http://www.devx.com/Java/Article/10688/0/pag e/2