Java; Java 2 Micro Edition - Sony Ericsson K700 White Paper

Java

Java 2 Micro Edition

Originally developed by Sun in 1991, Java is a
programming language used to develop
applications - utility programs, games, plug-ins etc.
- for different hardware and software platforms.
Users of Java-enabled devices can install new
applications and games to make their devices
more personal and adapt them to specific needs.
J2ME CLDC/MIDP
In 1999, Sun regrouped its Java technologies into
three platforms or editions. J2ME (Java 2 Micro
Edition) became the platform targeting "micro"
devices with small processors and memory
capacities, such as mobile phones, communicators
and PDAs. (The other two Java platforms are Java
2 Standard Edition, J2SE, and Java 2 Enterprise
Edition, J2EE).
J2ME addresses a variety of devices. To handle the
diversity, two concepts have been introduced –
configurations and profiles. A configuration defines
a minimum platform for a family of devices with
similar processing and memory capacities. A
profile targets a specific device category within that
family, for instance mobile phones.
Two J2ME configurations are available:
• CDC, Connected Device Configuration. This
configuration is aimed at devices such as PDAs.
• CLDC, Connected Limited Device Configura-
tion. This configuration is aimed at devices such
as mobile phones and pagers.
Figure 3. J2ME in detail
Current situation
So far, two profiles have been established for
J2ME:
• MIDP, Mobile Information Device Profile, and
• Personal Profile.
MIDP is connected to the CLDC configuration and
provides developers with essential information and
guidance when writing programs for mobile phones
and two-way pagers.
Personal Profile is linked to the CDC
configuration. Targeted at PDAs, this combination
replaces PersonalJava in J2ME.
CLDC/MIDP v. PersonalJava
Besides targeting different types of devices, the
main difference between J2ME CLDC and
PersonalJava from a user's point of view is that
applications written in J2ME CLDC can be
downloaded from the Internet. PersonalJava
applications are typically transferred to devices
from a PC via cable.
30
K700
White Paper
February 2004