The Mobile Service Architecture (MSA) specification defines a common architecture and programming platform for wireless handsets. Like its predecessor, Java Technology for the Wireless Industry (JSR 185), MSA is an umbrella Java specification, a collection of familiar, updated, and new JSRs that cooperate to support applications with a wide range of standardized capabilities.
Two flavors of MSA are defined: The basic MSA (JSR 248) addresses CLDC-based platforms, and the MSA-Advanced (JSR 249) addresses CDC-based platforms. The architectures define a comprehensive structure of APIs aimed at facilitating development and deployment of the widest possible variety of applications, in a form that will be easily portable across the broadest possible spectrum of mobile devices.
The basic MSA defines two stacks: a full MSA stack that comprises 16 JSRs and a subset of eight JSRs, as illustrated in Figure 3.
Figure 3: The MSA Specification APIs (JSR 248)
Some of the JSRs are mandatory, and others are conditionally mandatory. To comply with MSA, an implementation must support a mandatory JSR or one that is conditionally mandatory, that is, one that becomes mandatory when relevant conditions are true. A typical example of the latter is JSR 82, the Bluetooth API, which is not always required but must be supported if the device claims to support the Bluetooth wireless technology.
For an introduction to MSA, see the article The Mobile Service Architecture Specification.
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