Java Reference
In-Depth Information
SR 11.12
If the input is
42
the program defined
OutOfRangeException
is thrown in
main
, the message “Input value is out of range.” is printed along with the
stack trace that consists of just information about
CreatingExceptions.
main
, and the program terminates. If the input is -
3
, the same thing
happens. If the input is the string “thirty,” then a library defined
InputMismatchException
is thrown, a stack trace that consists of infor-
mation about five methods is printed, and the program terminates. I/O
exceptions are the topic of the next section of this textbook.
11.6
I/O Exceptions
SR 11.13
A stream is a sequential series of bytes that serves as a source of input
or a destination for output.
SR 11.14
The standard I/O streams in Java are
System.in
, the standard input
stream;
System.out
, the standard output stream; and
System.err
,
the standard error stream. Usually, standard input comes from the
keyboard and standard output and error go to a default window on
the monitor screen.
SR 11.15
The
Stream
object we have been using explicitly throughout this topic
is the
System.out
object. We have used it when printing output from
our programs. Sometimes we have also used the
System.in
object, to
create
Scanner
objects for reading input from the user.
SR 11.16
The
main
method definition of the
CreatingExceptions
program
does not include a
throws
InputMismatchException
clause, because
the
Scanner
class takes care of that—there is no need to repeat code
in the
main
method when it is already included in a helper class.
SR 11.17
The
main
method definition of the
TestData
program does not include
a
throws
FileNotFoundException
clause, because the
FileWriter
class takes care of that that—there is no need to repeat code in the
main
method when it is already included in a helper class.
SR 11.18
If the
PrintWriter
constructor of the
TestDate
class is passed the
fw
object instead of the
bw
object, the program still works. The only dif-
ference is that the program does not use the buffering capabilities of
the
BufferedWriter
class and therefore the processing may not be as
efficient.
11.7
Tool Tips and Mnemonics
SR 11.19
A tool tip is a small amount of text that can be set up to appear when
the cursor comes to rest on a component. It usually gives information
about that component.
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