Thursday, February 12, 2015
Autoboxing and Unboxing in Java
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.
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.
Till JDK 1.4
int x=10;
Integer i=new Integer(x); //boxing
From JDK 1.5
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.
Till JDK 1.4
int x=10;
Integer i=new Integer(x); //boxing
int z=i.intValue(); //unboxing
From JDK 1.5
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.
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
If you found anything wrong or missing in above tutorial then please mention it by commenting below.
Image Source: http://www.ntu.edu.sg/home/ehchua/programming/java/J5c_Collection.html
