DoJa is based on the Java ME CLDC API that is defined in the Java Community Process (JCP). DoJa is a profile defined by NTT DoCoMo to provide communications and other input-output processing, user interface (GUI) and other application features/functions unique to i-mode, and extension libraries defined by individual phone terminal makers to add original functions. However, in contrast with other Java ME profiles like Mobile Information Device Profile (MIDP) or Information Module Profile (IMP), DoJa is not defined as a Java Specification Request (JSR), hence it's often called a "proprietary" Java ME profile.
DoJa allows i-mode to offer more dynamic and interactive content than conventional HTML-based i-mode content. Java for i-mode consists of support for a version of CLDC and a version of the DoJa profile. CLDC support can be 1.0 or 1.1 depending on the handset. The DoJa profile was originally created for the local Japanese market with version 1.0 and version 2.0 more or less corresponding to MIDP 1.0 and MIDP 2.0. For the market outside of Japan a new API has been created, which is referred to as the Overseas Edition. Currently DoJa 1.5oe and DoJa 2.5oe are implemented on handsets sold in Europe. (The first DoJa handset with DoJa1.5oe is N341i launched in 2003 from NEC, and the first DoJa 2.5 handset is M430i launched in the beginning of 2005 from Mitsubishi.) The DoJa Profile provides for use with i-mode extension library (Java for i-mode profiles), including user interfaces and HTTP communications.
|DoJa Profile||Japanese handsets||Java CLDC version||Maximum JAR size||Maximum scratchpad|
|DoJa-1.0||503, 2101, 2002 Series||1.0||10/30kb||10/30/50kb|
|DoJa-2.x||504, 2051, 2102, 2701 Series||30kb||100/200kb|
|DoJa-3.0||505, 506 Series||30kb||200kb|
|DoJa-4.0LE||700, 701, 702 Series||1.1||30kb||200kb|
|DoJa-5.0||903 Series||1MB JAR+Scratch|
|Star-1.0||F-01A, etc., released 2008/Q4||2MB JAR+Scratch|
|Star-2.0||released 2011||10MB JAR+Scratch|
"Star" is the successor to DoJa, rather than being part of it, with access to modern hardware and services such as the accelerometer.