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Introduction
Information
devices like handset and PDA are expected to be more intelligent
and personalized with stronger functions that can utilize Internet
resources more conveniently. Catering for this demand, the Sun Company
launched Java 2 Platform Micro Edition (J2ME in short). Java-based
mobile value-added services make the content more dynamic and the
image functions more diverse: it enables the handset to download,
to be operated in off-line mode and to exploit the existing broadband
network intelligently, enjoying various services.
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Introduction of J2ME
Java
is a set of program language and platform launched by the Sun Microsystems
Company in middle 1995. Sun renamed Java as Java 2 after the JDK
1.2 edition was released in public, redefining the structure of
Java technology with three editions: the Enterprise Edition（J2EE）,
the Standard Edition（J2SE）, and the Micro Edition（J2ME）. J2EE suits
servers and is adopted in the application program development in
the enterprise environment; J2SE provides practical solutions for
desktop development and low-end commercial application, thus suits
common computers; and J2ME suits consumer electronics, which is
the best choice for consumables and embedded device development.
Sun
implements J2ME at two levels: the configuration level and the profile
level.
The configuration level is composed of the virtual machine, the
core class library and API. It provides a most basic and kernel
Java platform for the developers.
J2ME
defines two types of devices: the connected device and the connected
limited device. The connected device refers to those plugged, power-rich
and relatively big device with 32-digit or 64-digit processor and
512k+ storage. For instance, intelligent communicator, interactive
digital TV top box, etc. The connected limited device uses batteries,
which are small-sized with 16-digit or 32-digit processor and an
available storage of 160～512kB, such as handset, PDA, etc.
There
are two types of J2ME configurations for the above two devices,
namely CDC (Connected Device Configuration) and CLDC (Connected,
Limited Device Configuration). CDC adopts classical Java VM, while
CLDC uses KVM (The K Virtual Machine). To meet the requirement of
recourse-limited device, KVM has been revised as follows:
the
scale of the virtual machine and the class library has been reduced
to the standard of 50~80kB target code;
the
storage occupancy has decreased to dozens of kB;
effective
operation on equipment with 16-digit and 32-digit processor;
highly
transferable architecture with few code based on given machine and
platform;
multithreading
and waste reclaim are independent to the system;
able
to configure with the virtual machine components so as to fit a
given machine.
The
profile level also contains a set of API, which is mainly defined
for a given clan. It is implemented at a specific configuration
level while used at a specific profile level. The profile level
of CDLC devices like handsets and PDA are called MIDP (Mobile Information
Device Profile). MIDP adding up with CLDC makes a complete J2ME
architecture, see figure 1.
Figure 1 Architecture
As
shown in figure 1, the bottom part（MID）represents information device
hardware. Above the hardware is the system software of original
code, which contains the library files used for operation of the
system and the system. Still above is CLDC, which represents KVM
and the relevant library function defined by CLDC specifications.
It provides the most fundamental Java functions required by upper
Java API. Two types of API lie with CLDC: the MIDP API and the OEM
special API. The OEM special API extends MIDP-defined functions,
which may be provided by OEM for a give device, thus not transferable.
CLDC is the basis of MIDP and OEM special API. The top part in figure
1 shows possible application programs of MID:
MIDP application: The application program which only uses MIDP and
CLDC-defined API. This type of application program is developed
with MIDP specification, and is transferable.
OEM special application: OEM dedicated application program depends
on certain class that does not follow MIDP specifications. These
application programs are not transferable.
Original application: It is not developed with Java. It operates
with MID and local operation system.
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Java-based mobile value-added services provisioning
The
provision of Java-based mobile value-added services involves several
players including mobile users, handset venders, mobile operators,
mobile equipment providers, value-added services platform providers
and content providers. Java-based mobile value-added services system
is made up of three parts: handset terminal equipment, mobile Java
download platform and mobile Java application. Among them, the handset
terminal equipment requires virtual Java operation environment (KVM);
the mobile Java application download platform requires download,
upload, management and billing functions of Java applications; and
mobile Java applications must be based on Java specifications.
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Java’s advantages in mobile services
With
Java platform, the handset functions development cycle can be reduced
tremendously; programs can be transferred to other systems conveniently,
the handsets can be upgraded; and it will be easier for the third
party the participate in the development of handset functions.
Visiting
Internet with the WAP Brower is limited. For example, users cannot
visit the Internet directly but to be filtrated bye Gateway; it
is able to display WML only but not complicated figures; online
transactions increase load on the server, which lead to a slow rate;
and it cannot visit local storage.
However,
visiting Internet with Java-supported Client, users can reach all
the information on the Internet; realize high-rate online transactions
and can visit local storage. Hence the possibility of e-stamp, e-stock
and e-map.
It
is safe to say that Java brings intelligent and personalized handsets
for its users, who can customize their handsets by downloading new
services and application programs from the Internet. The handsets
will have dynamic content and various image functions. They will
be able to operate “off-line” and to utilize the existing network
broadband intelligently with rich and diverse services.
As
for the operators, Java is helpful when deciding technical and commercial
modes, which in turn leads the services development and content
of the value-added services providers, making various services content
and commercial modes possible. Besides, the cross-network provisioning
of services content is made possible because Java services is independent
to the communications network protocol.
The
development of application program and services will be made easier
with the wide use of Java platform. The handset vendors, content
providers and software developers can rapidly and easily develop
and update service content/program, thus rapidly launch their products
in the market.
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Java-based mobile applications
Java-based
value-added services applications may involve several types:
Games
& Entertainment: Java enables the handset with rich image functions.
What’s more, Java handsets embrace local implementation capability,
which makes games and entertainment more appealing.
Mobile
commerce: Handset users can go shopping, reserve hotels/air tickets
with mobile phones. Java can be used to develop applications that
are capable of dynamic display of data and charts. With Java, transactions
can be made more rapid and convenient. Mobile banks, stock information
and operation will be made easier at the same time.
Information:
it is possible to provide personalized and customized services for
users with Java handset. Thanks to the high availability and visibility
of Java handset application, users may take it as the receiver of
news, weather and traffic information which is of their concern.
Location-based services can also be improved with Java.
Mobile
business and enterprise services: though without notebook, people
can send and receive e-mails，participate in the business process
of their companies and examine and review documents, etc.
E-publication:
the e-publication of Java-based wireless services enables people
to read the latest news and enjoy reading as much as they can.
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Development of mobile Java services
More
than 3.5million Java handset had been launched in the market by
the end of May 2001. It is estimated by ARC Group that, around 60%
of all the handsets, i.e. 429 million handsets will be Java based
by 2003. According to surveys done by Evans Data Co. in 2001, over
33% wireless developers are ready for J2ME based development.
NTT
DoCoMo of Japan launched I-appli Java handset services on January
26, 2001. It sold 230,000 handsets in the first week and 9,600,000
till December 9,2001. When this service was launched, there were
36 content providers, among which 80% provided entertainment content.
They had developed more than 5,000 applications by May 2001.
The
ez-l CDMA project of LG Telecom of Korea launched Java-based services
in September 2000. By the end of 2001, handset users had exceeded
500,000 with over 300 applications. 70% of the data service users
are involved in Java services.
Four
mobile operators of Korea have been providing Java or Brew (Qualcom’s
competing product to J2ME) based application. Softbank Research
estimated in 2001 that VM-based services in Korea will add up to
600 million US dollars by 2005.
Other
mobile operators have launched Java-based services such as Nextel
Communications of the USA, J-Phone（PDC） of Japan, KDDI（CDMA） of
Japan, Sprint PCS, Hutchison of Hong Kong, Hong Kong Telecom, Far
Eastone of Taiwan, Omnitel, One2One, Telefonica, Vodafone, etc.
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Conclusion
With
Java-based mobile value-added services system, handset users will
enjoy rich and diverse services by downloading application program
from the Internet, while vendors, mobile operators, content providers
may benefit as well. It is sound to believe, therefore, that Java-based
mobile value-added services will have a bright future, and we will
be able to enjoy live and personal mobile value-added services brought
by Java not within too long a time.
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Background of the author:
Tang Yong gained his master’s degree from
Beijing University of Posts and telecommunications in 1996. He’s
currently working with the Development Strategy Department of Beijing
Mobile Communications Co., Ltd.
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