DoJa is the Java profile used by NTT DoCoMo for their i-mode™ service. Since it is completely independent from MIDP at the package level, JV-Lite™2 Wireless Edition implements both DoJa and MIDP.

DoJa functions on J2ME™ CLDC APIs that were defined by the Java Community Process (JCP), the DoJa extension library that was defined by NTT DoCoMo to provide communications and other input-output processing, graphical user interface (GUI) and other features/functions unique to i-mode, and extension libraries defined by individual phone terminal makers to add original functions. Please note that DoJa applications that use an API to provide a function that is unique to a particular phone terminal can only work with that particular terminal.

DoJa allows i-mode to offer more dynamic and interactive content than conventional HTML-based i-mode content. Java for i-mode consists of J2ME*1 CLDC*2, a Java platform that Sun Microsystems developed for use with consumer electronics and embedded devices, and the i-mode extension library (Java for i-mode profiles), including user interfaces and HTTP communications.

Functions and Features

Java for i-mode has the Following Functional Features:

1. Permanent Storage Support
   DoJa applications can save generated data or data downloaded from the network to the mobile phone terminal. This mechanism is called ScratchPad.
   
2. Multimedia Data Support
   DoJa supports playback of multimedia data, such as i-melody and i-anime (animation GIF). The multimedia data can be included in the Java application file (JAR file) or downloaded from the network when the application is run.
   
3. Automatic Application Activation
   DoJa supports automatic activation of an application. This enables Java for i-mode to create agent-type applications, including those that start up automatically at a certain time interval and download the latest data from servers.
   
4. Enhanced Data Security
   With Java for i-mode, content providers can enhance the data security of their service by installing a Java application that incorporates their original security function in the user's phone terminal.

Software Architecture

JV-Lite2 Wireless Edition for DoJa Software Architecture

System Requirements:
The maximum data size for a Java for i-mode application is 10KB. The phone terminal secures at least 5KB for each ScratchPad. Java-enabled i-mode terminals can each save at least three JAR files and ScratchPads.