Java Reference
In-Depth Information
Listing 3-4. String with escape sequence
String errorMessage = "The whatsit didn't work!\nCheck the doohickey.";
System.out.println(errorMessage);
That code snippet produces the output in Listing 3-5.
Listing 3-5. Newline output
The whatsit didn't work!
Check the doohickey.
Wrapper Classes
Each of the primitives (remember,
String
is an object rather than a primitive) has a corresponding class
that provides several useful abilities that are otherwise unavailable to a primitive. You can think of the
wrapper classes as each being a package of useful abilities wrapped around a primitive of the
corresponding type. Table 3-4 shows the corresponding class for each primitive:
Table 3-4. Wrapper classes
Primitive Class
byte
Byte
short
Short
int
Integer
long
Long
float
Float
double Double
boolean Boolean
char
Character
The most commonly used methods of those classes are the various
parse
,
Value
, and
valueOf
methods, because those methods let you turn a
String
into a primitive. Each class also supports
toString
methods to turn primitives into
String
objects. Listing 3-6 shows what you can do with an
int
primitive.