One of the better aspects of the Java language is that it has
defined a very clear packaging mechanism for categorizing and managing
the external API. Contrast this with a language like C, where external
symbols may be found in the C library itself or in any of dozens of
other libraries, with no clearly defined naming conventions.[1] APIs consist of one or more packages; packages consist of classes; classes consist of methods and fields. Anybody can create a package, with one
important restriction: you or I cannot create a package whose name
begins with the four letters java.
Packages named java. or javax. are reserved
for use by Sun Microsystems’ Java developers. When Java was new, there
were about a dozen packages in a structure that is very much still with
us; some of these are shown in Table 23-1.
Table 23-1. Java packages basic structure
Name | Function |
|---|---|
| Applets for browser use |
| Graphical User Interface |
| Intrinsic classes (strings, etc.) |
| Networking (sockets) |
| Reading and writing |
| Utilities (collections, date) |
Many packages have since been added, but the initial structure has stood the test of time fairly well. In this chapter, I show you how to create and document your own packages, and then discuss a number of issues related to deploying your package in various ways on various platforms.
You want to be able to import classes and/or ...
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