Designing and Coding

Designing and Coding
Before you can begin an actual development cycle, you must first create the directory structure
that will support the development of your MIDlet suite. A MIDlet suite is a collection of MIDlets
that share common application resources. You'll learn further details about these shared MIDlet
resources in later chapters of this book.
I first create a directory called HelloWorld, which is the name of our first example application,
under the apps/ directory of the wireless toolkit installation. This directory is the root of your
new project. A project is an organized aggregation of resources—source code, resource files,
compiled files—specific to one or more related applications.
The project root directory contains the subdirectories shown in the following sample code:
$ pwd
/cygdrive/c/J2mewtk/apps/HelloWorld
$ ls -F
bin/ classes/ res/ src/ tmpclasses/
There is a reason for using this precise directory structure, which I will explain later when you
learn how to use the Wireless Toolkit Emulator. However, even if you don't plan to use the J2ME
Wireless Toolkit, this organizational structure is a reasonable one to start with. Table 2.1 explains
the contents and purpose of these directories.
I won't discuss actual application design here, because that topic is beyond the scope of this
chapter. The goal here is not to discuss how to design Java applications or even MIDP
applications. Subsequent chapters, however, will talk about organization of MIDP applications.
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Table 2.1. Subdirectories of Projects Created by the J2ME Wireless Toolkit
Subdirectory
Name
Directory Contents
bin Application files: .jar file, .jad file, MANIFEST.MF
classes Compiled and preverified .class files
res Application resource files, such as .png formatted image files in
PNG format
src Application source files
tmpclasses Compiled, unverified .class files