Trail: Essential Java Classes
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Setting Program Attributes
Java programs run within an environment that contains system
attributes: a host machine, a user, a current directory, and an
operating system. A Java program also can set up its own configurable
attributes, called program attributes. Program attributes allow the
user to configure various startup options, preferred window size, and
so on for the program. Sometimes the term preferences
is used instead of program attributes.
System attributes are maintained by the System
class and are covered later in
System Properties.
Java programs can set their own set
of program attributes through three mechanisms: properties,
command-line arguments, and applet parameters.
A property defines attributes on a persistent basis. That is, you use
properties when attribute values need to persist between invocations of
a program. This section
shows you how to do this in your programs.
A command-line argument defines attributes for Java applications on a
nonpersistent basis. You use command-line arguments to set one or more
attributes for a single invocation of an application.
This section shows how to accept and process command-line
arguments in a Java program.
Applet Parameters
An applet parameter is similar to a command-line argument,
except that it is used with applets, not applications.
Use applet parameters to set
one or more attributes for a single invocation of an applet. For
information about applet parameters, see
Defining and Using Applet Parameters .
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