in detail in Part II, but they are introduced here because they relate directly to Java's
autoboxing feature.
The type wrappers are Double, Float, Long, Integer, Short, Byte, Character, and Boolean.
These classes offer a wide array of methods that allow you to fully integrate the primitive
types into Java's object hierarchy. Each is briefly examined next.
Character
Character is a wrapper around a char. The constructor for Character is
Character(char ch)
Here, ch specifies the character that will be wrapped by the Character object being created.
To obtain the char value contained in a Character object, call charValue( ), shown here:
char charValue( )
It returns the encapsulated character.
Boolean
Boolean is a wrapper around boolean values. It defines these constructors:
Boolean(boolean boolValue)
Boolean(String boolString)
In the first version, boolValue must be either true or false. In the second version, if boolString
contains the string "true" (in uppercase or lowercase), then the new Boolean object will be
true. Otherwise, it will be false.
To obtain a boolean value from a Boolean object, use booleanValue( ), shown here:
boolean booleanValue( )
It returns the boolean equivalent of the invoking object.
The Numeric Type Wrappers
By far, the most commonly used type wrappers are those that represent numeric values.
These are Byte, Short, Integer, Long, Float, and Double. All of the numeric type wrappers
inherit the abstract class Number. Number declares methods that return the value of an
object in each of the different number formats. These methods are shown here:
byte byteValue( )
double doubleValue( )
float floatValue( )
int intValue( )
long longValue( )
short shortValue( )
For example, doubleValue( ) returns the value of an object as a double, floatValue( )
returns the value as a float, and so on. These methods are implemented by each of the
numeric type wrappers.
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