It's all well and good that devices will fall within one Configuration or the other. For example, a typical cellular phone, PDA and pager will all fit the guidelines of the CLDC. However, what seems limiting to one device in a Configuration may be an abundance to another. Recall the analogy of the cellular phone screen size versus that of a PDA.
To address this broad range of capabilities, and to provide for more flexibility as technology changes, Sun introduced the concept of a Profile to the J2ME platform.
A Profile is an extension, if you will, to a Configuration. It provides the libraries for a developer to write applications for a particular type of device. For example, the Mobile Information Device Profile (MIDP) defines APIs for user interface components, input and event handling, persistent storage, networking and timers, taking into consideration the screen and memory limitations of mobile devices.
Beginning in Chapter 3, the remainder of this book will focus on MIDP specifically. This will include everything from the hardware and software requirements to complete coverage of all the APIs.
How are Configurations and Profiles Developed?
Excerpt from J2ME FAQ (http://java.sun.com/j2me/faq.html): Configurations and Profiles are defined by open industry working groups utilizing Sun's Java Community Process Program. In this way industries can decide for themselves what elements are necessary to provide a complete solution targeted at their industry. For more information on the Sun Community Process Program, see: http://jcp.org