In addition, NTT DoCoMo control the intellectual property rights to
content and can ensure the security and, more importantly, the homo-
geneity of their technical implementations. This means that they do not
have to plan mitigation strategies for the kinds of fragmentation problems
seen in Java ME mainstream profiles to date. Furthermore, NTT DoCoMo
can produce new versions of their DoJa profile to their own time schedule
to meet the changes in customer demands as new technologies evolve.
To put that into perspective, there are currently some seven or more
versions of the DoJa profile for use inside Japan, as well as another two
overseas editions. Compare this to MIDP, where the 3.0 specification is
still being finalized.
Given all of this, it is little wonder that NTT DoCoMo has taken a
winning lead in this highly competitive market and has managed to stay
there so far. And while it's all very new and foreign to us, looking at
what's happening in Japan now gives us a view into our probable future.
Many of the mobile device technologies and infrastructures being used
in Japan may very well become commonplace over the next decade
in cities such as London, New York, and maybe even Sydney! So take
this chance to get familiar with this part of the world and consider the
opportunities available because with DoJa, you can sell your applications
to a technologically savvy customer base of more than 50million people,
many of whom regularly spend money and time on mobile games.
7.2 DoJa - the Basics
DoJa applications are small programs, written in Java, known as 'i-
Appli'. To get started developing with DoJa, a free toolkit, not unlike
Sun's Wireless Toolkit, is available for download from NTT DoCoMo
at www.doja-developer.net/download. This is a very simple tool that
supports basic i-Appli development using a text editor, such as Notepad.
It also lets you set run-time configuration parameters and various network
settings and comes with an Eclipse plug-in (available when you choose
the Custom installation option, as shown in Figure 7.1).
Detailed use of this toolkit is discussed in [Stichbury 2008, Section
10.4], so we won't go any further with this here. Also, developers usually
use an IDE such as Eclipse for effective DoJa development. However, the
toolkit is still a great way to get started if you want to use it. We walk
through setting up Eclipse in Section 7.5.
Like MIDlets, i-Appli are deployed as JAR files with an accompanying
metadata file called the Application Descriptor File (ADF) which has a
role analogous to the JAD file in MIDP. A DoJa profile implementation