method local class- final vairable

[hari harann]

Anybody could explain me why a inner class object can use the local variables of the method the inner class is in when these ones are declared final.

It's confused to get it when you think that the scope of a local variable is limited to the method the variable is declared in. so, any special reason??

[Henry Wong]

Well, technically, it is not using the local variable. If the local variable is final, the inner class can assume that the variable will not change, and hence, make a copy of it.

Henry

[Ankit Garg]

Here's the code

void method(final int a,int b)
{
    final int c = 10;
    int d = 20;
    class Local
    {
        void display()
        {
            System.out.println(a);
            //System.out.println(b);  //error
            System.out.println(c);
            //System.out.println(d);  //error
        }
    }
    new Local().display();
}

Now after compilation the code would look as (I have removed the commented lines for simplicity...)

void method(final int a,int b)
{
    final int c = 10;
    int d = 20;
    new Local$1([B]a[/B]).display();
}
class Local$1
{
   final int [B]val$a[/B];
   Local$1(int a)
   {
        val$a = a;
   }
   void display()
   {
       System.out.println([B]val$a[/B]);  //value accessed from local field
 
       System.out.println([B]10[/B]);  //value replaced by literal
 
   }
}

[hari harann]

Thanks Ankit..but i wonder where from do you get all these details(i have read lot of your replys in the forum).. if you could give any resource i think that could help scjp aspirants a lot...

[hari harann]

Thanks Ankit..but i wonder where from do you get all these details(i have read lot of your replys in the forum).. if you could give any resource i think that could help scjp aspirants a lot...

[chander shivdasani]

The class cannot use the variables that are not Final.
Because,

The scope of method specific variable is only inside the method. The variable dies once the control exits the block.

[Ankit Garg]

since you asked for so hari you can read my blog...the link is in my signature....