WRAPPER CLASSES

  Primitive data types may be converted into object types by using the wrapper classes contained in Java.

  The table below shows the simple data types and their corresponding wrapper class types:

Simple Type	Wrapper Class
Boolean	Boolean
Char	Character
Double	Double
Float	Float
Int	Integer
Long	Long

             Converting Primitive numbers to object number using constructor methods:

Constructor Calling	Conversion Action
Integer intval=new Integer(i);	Primitive integer to Integer object.
Float floatval=new Float(f);	Primitive float to Float object.
Double doubleval=new Double(d);	Primitive double to Double object.
Long longval=new Long(l);	Primitive long to Long object.

             Converting object number to Primitive numbers using typeValue() methods:

Method Calling	Conversion Action
int i= intval.intValue();	Object to Primitive integer.
float f= floatval. floatValue();	Object to Primitive float.
double d=doubleval.doubleValue();	Object to Primitive double.
long l=longval.longValue();	Object to Primitive long.

             Converting number to String using toString() method:

Method Calling	Conversion Action
Str=Integer.toString(i);	Primitive integer to string.
Str=Float.toString(f);	Primitive float to string.
Str=Double.toString(d);	Primitive double to string.
Str=Long.toString(l);	Primitive long to string.

             Converting String object to numeric objects using the static methodValueOf():

Method Calling	Conversion Action
doubleval=Double.ValueOf(str);	Convert String to Double object.
floatval=Float.ValueOf(str);	Convert String to Float object.
intval=Integer.ValueOf(str);	Convert String to Integer object.
longval=Long.ValueOf(str);	Convert String to Long object.

             Converting Numeric String to primitive number using parsing method:

Method Calling	Conversion Action
int i=Integer.parseInt(str);	Convert String to primitive integer.
long l=Long.parseLong(str);	Convert String to primitive long.