unboxing issues

[Adeyemi Adeseye]

can someone explain why this code gives a null pointer exception at runtime

 public calss Boxer1{
Integer i;
int x;
public Boxer1(int y){
x=i+y;
Sytem.out.print(x);
}
public static void main (String... args)
{
new Boxer1(new Integer(4));
}
}

[Kamil Wojcik]

because default value for Integer (it's an Object!) is NULL

[Adeyemi Adeseye]

oh, tanks, that skipped my mind.