Java Reference
In-Depth Information
char
tab
=
'\t'
,
nul
=
'\
000
'
,
aleph
=
'\u05D0'
,
slash
=
'\\'
;
Table 2-2
lists the escape characters that can be used in
char
literals. These characā
ters can also be used in string literals, which are covered in the next section.
Table 2-2. Java escape characters
Escape
sequence
Character value
Backspace
\b
Horizontal tab
\t
Newline
\n
Form feed
\f
Carriage return
\r
\
"
Double quote
\
'
Single quote
Backslash
\\
\
xxx
The Latin-1 character with the encoding
xxx
, where
xxx
is an octal (base 8) number
between 000 and 377. The forms
\
x
and
\
xx
are also legal, as in
\0
, but are not
recommended because they can cause diiculties in string constants where the escape
sequence is followed by a regular digit. This form is generally discouraged in favor of the
\uXXXX
form.
\u
xxxx
The Unicode character with encoding
xxxx
, where
xxxx
is four hexadecimal digits.
Unicode escapes can appear anywhere in a Java program, not only in character and string
literals.
char
values can be converted to and from the various integral types, and the
char
data type is a 16-bit integral type. Unlike
byte
,
short
,
int
, and
long
, however,
char
is an unsigned type. The
Character
class defines a number of useful
static
methods for working with characters, including
isDigit()
,
isJavaLetter()
,
isLo
werCase()
, and
toUpperCase()
.
The Java language and its
char
type were designed with Unicode in mind. The
Unicode standard is evolving, however, and each new version of Java adopts a new
version of Unicode. Java 7 uses Unicode 6.0 and Java 8 uses Unicode 6.2.
Recent releases of Unicode include characters whose encodings, or
codepoints
, do
not fit in 16 bits. These supplementary characters, which are mostly infrequently