final variable error

[gurneeraj singh]

 class A {
final Object obj;
A(){
obj="s";  \\---------LINE 1
System.out.println(obj instanceof Object);
Integer i=new Integer("1");
obj=i;    \\---------LINE 2
}
public static void main(String args[]) {
A a=new A();
System.out.println(a.obj);
}
}   

Why above code is giving error on Line 2 that the variable obj has not been initilized, when it has already been initilized on Line 1.

[Jelle Klap]

If you compile this code you should get a compiler error stating that the variable might already have been initialized, because it has.
The compiler should not complain about the variable possibly not having been initialized. Are you sure you didn't misread the error message?

[Muhammad Saifuddin]

Why above code is giving error on Line 2 that the variable obj has not been initilized, when it has already been initilized on Line 1.

because of the final keywords. Once a final variable has been assigned, it always contains the same value. means the value of a final variable cannot change after it has been initialized.

[Mamadou Touré]

You should get the following error
variable obj might already have been assigned

[sridhar row]

final instance variables do not have a default value. so basically it gets value assigned in LINE 1 (obj="s"; //LINE 1)and therefore in LINE 2 it gives a error when you try to change its value.

[Raghavan Muthu]

Please keep this in mind that a final variable can get its value until the constructor of the instance completes! But it can get only once!

If any of the above fails, you obviously get an exception! :cheers: