Inner class doubt

[raja kanak]

    
public class DemoMethodLocal {
    public static void main(String... args) {
    }
    void doStuff() {
        final int a=6;
        final int b;
        b=5;
        class MethodLocalClass {
            a=6;   //1
        }
    }
}

The above code shows error at //1 while compiling. I thought since a is declared as final, it can be used inside MethodLocalClass. But what went wrong?

[Jesse Custer]

You are reassigning a final variable. You cannot give 'a' a new value.

[raja kanak]

Originally posted by Jesse Custer:
You are reassigning a final variable. You cannot give 'a' a new value.

I changed //1 as
System.out.println(a);

Still it is problem, "Identifier expected".

[ShivKumar Rajawat]

Hi Live,
After this replacement your inner class structure becomes :

class MethodLocalClass {
System.out.println(a);
}
instead of puuting this statement directly inside the class , could you please try creating a member method and then put this statem,ent in that method.

[raja kanak]

    
public class DemoMethodLocal {
    public static void main(String... args) {
    }
    void doStuff() {
        final int a;     //0
        final int b;
        b=5;
        class MethodLocalClass {
           void method() {
               a=5;                     //1
               System.out.println(a);   //2
           }
        }
    }
}

Thanks ShivKumar for your reply. As per your suggestion I modified my code as at //0 final int a; and at //1 included a=5 which gives compile time error "Cannot assign a value to final variable". So i commented //1 and again it complains that "variable a might not have been intialized".

That means we must initialize the variable a before the MethodLocalClass definition.

Again at //0 i removed final modifier, then the compiler error is "local variable a is accessed from within inner class; needs to be declared final"

Conclusion: To access a local variable inside inner class, that variable should be declared final as well as it should be initialized outside the inner class.

Please correct me, if I am wrong.

raja

[Chris Hurst]

JSL.....

A blank final (�4.12.4) field of a lexically enclosing class may
not be assigned within an inner class.

and ...

Any local variable, formal method parameter or exception handler parameter used but not declared in an inner class must be declared final. Any local variable, used but not declared in an inner class must be definitely assigned before the body of the inner class.

Switch statements can be fun in what they do an don't allow with finals too.