rom the earliest days of J2ME, network connectivity has been a central focus of the design. So much so that a generic architecture, referred to as the Generic Connection Framework (GCF), was created to standardize not only how applications create network connections but the associated connection interfaces device manufacturers must implement. The GCF is a fundamental part of J2ME and is available to all application profiles including Personal Profile
and the Mobile Information Device Profile (MIDP).
|Figure 1. The J2ME Stack: The configuration layer forms the basis for the J2ME stack and defines the characteristics of the J2ME.|
In order to make the GCF available to all J2ME application profiles, the GCF is implemented in the configuration layer. The configuration layer is a set of J2ME libraries that form the basis of any J2ME architecture. Packages such as java.lang, java.util, java.io, and so forth can be found in the configuration layer. Figure 1 shows how the configuration layer relates to the profile layer in J2ME.