Java Reference
In-Depth Information
Wrapping Up
Java ME's strength as a platform lies in its write-once, run-anywhere nature; unfortu-
nately, this laudable goal is perpetually threatened by the open nature of the Java
community, which encourages and embraces growth, leading to API and platform
fragmentation. The Java community works to both extend the APIs available to Java
ME as well as stem the fragmentation of the Java ME platform through the JCP, which
issues JSRs that document additional APIs or combinations of APIs to enable new
applications and services. Three key JSRs are working to reduce Java ME platform
fragmentation by defining collections of Java ME APIs that should be included on as
many devices as possible.
The first, JSR 185, defines the JTWI, a bare-bones mobile handset that supports
the CLDC, the MIDP, and WMA. It may also support some audio multimedia through
the MMAPI. Most of today's Java ME-enabled devices on the market explicitly comply
with the JTWI, either as a deliberate, verified goal of the device manufacturer or as a
matter of course.
The second two, JSRs 248 and 249, build on the JTWI and define additional
platforms that require an increasing number of APIs. These JSRs permit you to rely
on the presence of those required APIs for file system access, MMAPI, SATSA, Mobile
3D Graphics API, WMA, and SVG API, as well as APIs that implement new network
features such as SIP and IMS.