Final Funda

[Harvinder Singh]

/*
When I remove the comment compiler complains:
cannot assign a value to final variable i=10;
^
And when I put the comment then compiler complains:
Variable i might not have been intiallized
Is it necessary to assign the value to a final variable at the same place where
it is declared(then it compiles)???
*/
class ModifierFunda{
final int i=10;

void FinalInit(){
//i=10;
}
}

[Yi Meng]

Originally posted by Harvinder Singh:
/*
When I remove the comment compiler complains:
cannot assign a value to final variable i=10;
^
And when I put the comment then compiler complains:
Variable i might not have been intiallized
Is it necessary to assign the value to a final variable at the same place where
it is declared(then it compiles)???
*/
class ModifierFunda{
final int i=10;

void FinalInit(){
//i=10;
}
}

You are to make sure that the final variable is only initialized once and only once, and also initialized before constructor returns for non-static final attribute, for static final attribute you are to make sure that it gets initialized before finishing loading the class. That means:
1. non-static final variables:
i. Initialize it when declared. i.e. final int i = 5;
ii. declare it and explicitly initialize it in each constructor. i.e.

 class A {
    private final int i;
    A() {   
       i = 5;
    }
}
 

2. static final attribute
i. Initialize it when declared. i.e. static final int i = 5;
ii. declare it and explicitly initialize it in a static initializer. i.e.

 class A {
    public static final int i;
    static{   
       i = 5;
    }
}
 

[Anand Sidharth]

Yi Meng,
That was was very well explained.