Java Version 2 Mobile Edition (J2ME) is a compact version of
Sun’s Java technology targeted for embedded consumer electronics.
J2ME includes a set of developer tools and supplies to
be used in mobile applications. As with other Java platforms,
key advantages can be realized using J2ME: Consistency across
products, code portability, reliable network delivery, and leveraging
of the Java programming language. It is also upwardly
scalable to work with other Java platforms.
Sun Microsystems is targeting J2ME for devices with limited
hardware resources such as PDAs, cellular phones, and other
consumer electronics and embedded devices with as little as 128 Kb of RAM. J2ME actually consists of a set of profiles and
configurations as in Figure 2-12. Each profile is defined for a
particular type of device—cell phones, PDAs, smart appliances,
and others. The profile specifies the classes, methods, and configuration
needed. The configuration includes a minimum set of
class libraries required for the particular type of device and a
specification of a Java Virtual Machine (JVM) required to support
the device.
J2ME technology enables wireless device manufacturers,
service providers, and content providers to perform rapid, cost
effective development of new features and applications. The
latest release includes emulation tools for Palm OS, RIM, and
others. Also included is support for Secure Hypertext Transfer
Protocol (S-HTTP).
Using J2ME, developers can write applications such as a
WAP browser for a cellular phone or a PDA. J2ME allows for
third-party developers to create applications that run on manufacturers’
devices without providing proprietary information or
special application programming interfaces and documentation.