Autoboxing and Unboxing in Java
Before understanding autoboxing and unboxing in java we must know what is wrapper class. So lets take a look on it.
Wrapper Class
A wrapper class wraps around a primitive data type and gives it an object appearance. This wrapper class object can be used whenever the primitive data type is required as an object.
Autoboxing in Java
The process of converting primitive data type into wrapper
class object automatically is known as autoboxing. This feature was added from JDK
1.5.
class object automatically is known as autoboxing. This feature was added from JDK
1.5.
The example for autoboxing is given below. Till JDK 1.4 we
have to manually do the conversion of primitive data type into wrapper class
and vice-versa using wrapper class method but from JDK 1.5 it is done
automatically.
have to manually do the conversion of primitive data type into wrapper class
and vice-versa using wrapper class method but from JDK 1.5 it is done
automatically.
Till JDK 1.4
|
1 2 |
int x=10; Integer i=new Integer(x); //boxing |
From JDK 1.5
|
1 2 |
int x=10; Integer i=x; //autoboxing |
Unboxing in Java
The process of converting wrapper class object into
primitive data type automatically is called unboxing.
primitive data type automatically is called unboxing.
Till JDK 1.4
|
1 2 3 |
int x=10; Integer i=new Integer(x); //boxing int z=i.intValue(); //unboxing |
From JDK 1.5
|
1 2 3 |
int x=10; Integer i=x; //autoboxing int z=i; //unboxing |
A list of primitive data type with their corresponding
wrapper class is given below.
wrapper class is given below.
|
Primitive
Data Type |
Wrapper
Class |
|
byte
|
Byte
|
|
short
|
Short
|
|
int
|
Integer
|
|
long
|
Long
|
|
float
|
Float
|
|
double
|
Double
|
|
char
|
Character
|
|
boolean
|
boolean
|
.png "Autoboxing and Unboxing in Java (Wrapper Class)")
Video Tutorial to Explain Autoboxing and Unboxing in Java
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