Autoboxing unboxing in Java - Java Tutorials

Autoboxing and Unboxing

The Autoboxing and Unboxing  was released with the Java 5.

Autoboxing

During assignment, the automatic transformation of primitive  type(int, float, double etc.) into their object equivalents or wrapper type(Integer, Float, Double,etc) is known as Autoboxing.

During assignment or calling of constructor, the automatic transformation of wrapper types into their primitive equivalent  is known as Unboxing.

Conversion of int into Integer

int inative = 0;

inative = new Integer(5); // auto-unboxing

Integer intObject = 5; // autoboxing

Storing int a into vector vt

int a = 10;

Vector <integer> vt = new Vector <integer> ();

vt.add(a);

int n = vt.elementAt(0); </integer></integer>

Autoboxing also works with comparison

int a = 10;

Integer b = 10;

System.out.println(a==b);

Output of the above code will be :

EXAMPLE

Boxing/Unboxing of Character value :

public class MainClass {
public static void main(String args[]) {
Boolean booleanObject = true;

if (booleanObject){
System.out.println("b is true");
}

Character ch = 'x'; // box a char
char ch2 = ch; // unbox a char

System.out.println("ch2 is " + ch2);
}
}

Output