7.2.1

Storing Packages in a File System

PACKAGES

applet

awt

io

lang

net

util

corresponding to the standard packages

java.applet

,

java.awt

,

java.io

,

java.lang

,

java.net

, and

java.util

 that are defined as part of the standard

Java Application Programming Interface.

Still continuing the example, if we were to look inside the directory

util

, we

might see the following files:

BitSet.java

Observable.java

BitSet.class

Observable.class

Date.java

Observer.java

Date.class

Observer.class

Dictionary.java

Properties.java

Dictionary.class

Properties.class

EmptyStackException.java

Random.java

EmptyStackException.class

Random.class

Enumeration.java

Stack.java

Enumeration.class

Stack.class

Hashtable.java

StringTokenizer.java

Hashtable.class

StringTokenizer.class

NoSuchElementException.java

Vector.java

NoSuchElementException.class

Vector.class

where each of the

.java

 files contains the source for a compilation unit ( 7.3)

that contains the definition of a class or interface whose binary compiled form is

contained in the corresponding

.class

 file.

Under this simple organization of packages, an implementation of Java would

transform a package name into a pathname by concatenating the components of

the package name, placing a file name separator (directory indicator) between

adjacent components. For example, if this simple organization were used on a

UNIX system, where the file name separator is

/

, the package name:

jag.scrabble.board

would be transformed into the directory name:

jag/scrabble/board

and:

COM.Sun.sunsoft.DOE

would be transformed to the directory name:

COM/Sun/sunsoft/DOE

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