why 'method local inner class' can only access final variable?

[ankur rathi]

 
 
public class OC{
 
void m() {
int i = 0;
 
class IC {
void m1() {
System.out.println(i);
}
}
}
}
 

why i should be final?

Thanks.

[vidya sagar]

why i should be final?

Because local variables of the method live on the stack, and exist only
for the lifetime of the method.When the method ends, the stack frame is blown away and the variable is history. But even after the method completes,the inner class object created within it might still be alive on the heap if, for example, a reference to it was passed into some other code and then stored in an instance variable. Because the local variables aren�t guaranteed to be alive as long as the method-local inner class object, the inner class object can�t use them.Unless the local variables are marked final!

[Preetha Vasudevan]

hi rathi
I think i got ur question the reason why the inner class can access only final variable because local varibale or formal parameters declared inside the method has a block scpoe and if the inner class accesses one of these variables which are not declared as final then the variable will go out of scope after the method exits.if it is declared final the variable can be used in the inner class even if the method exits..

I hope i have cleared ur doubt even though it sounds confusing!!

[A Kumar]

Hi,
Can you tell me where the final variables are stored during these access...

[Lalitha Gottumukkula]

Vidya Sagar,

But even after the method completes,the inner class object created within it might still be alive on the heap if, for example, a reference to it was passed into some other code and then stored in an instance variable.

Didn't get clearly. Can you explain this scenario with an example ?

Thanks,
Lalitha.