Java Reference
In-Depth Information
Notice how each value is located. Since each
double
value is 8 bytes long, each value starts
on an 8-byte boundary. Thus, the first value is located at zero, the second begins at byte 8,
the third starts at byte 16, and so on. Thus, to read the fourth value, the program seeks to
location 24.
Ask the Expert
Q
:
In looking through the documentation provided by the JDK, I noticed a class
called
Console.
Is this a class that I can use to perform console-based I/O?
A
:
The short answer is Yes. The
Console
class was added by JDK 6, and it is used to
read from and write to the console.
Console
is primarily a convenience class because
most of its functionality is available through
System.in
and
System.out
. However,
its use can simplify some types of console interactions, especially when reading
strings from the console.
Console
supplies no constructors. Instead, a
Console
object is obtained by calling
Sys-
tem.console( )
. It is shown here.
static Console console( )
If a console is available, then a reference to it is returned. Otherwise,
null
is returned. A
console may not be available in all cases, such as when a program runs as a background
task. Therefore, if
null
is returned, no console I/O is possible.
Console
defines several methods that perform I/O, such as
readLine( )
and
printf( )
. It
also defines a method called
readPassword( )
, which can be used to obtain a password. It
lets your application read a password without echoing what is typed. You can also obtain a
reference to the
Reader
and the
Writer
that are attached to the console. In general,
Con-
sole
is a class that you may find useful for some types of applications.
