Is it possible to initialize a final variable after declaring..?

Question

Is this even possible, few argue its possible and i saw it here too link.. but when i personally tried it gives me compile time errors..

i mean this,

Class A{
    private final String data;

    public A(){
        data = "new string";
    }
}

Thanks in advance..

Maybe your compile time error relates to upper-case 'Class'. The rest is perfectly fine and must compile. — home, Feb 25 '12 at 09:03
**The blank final field data may not have been initialized**... this is what i get.. — ngesh, Feb 25 '12 at 09:05
If you are sick, do you send your wife to the doctor? Show us the real code. — JB Nizet, Feb 25 '12 at 09:08
This code doesn't compile due to the Class in upper-case. So this is not the real code, or at least there is an other compile error, as already said by the other comments. — JB Nizet, Feb 25 '12 at 09:13

Boris Strandjev · Accepted Answer · 2017-12-11T07:46:52.727

7

Yes, it is possible. Class is written with small case c. Otherwise your code is perfectly fine (except for identation):

public class A {
   private final String data;

   public A() {
      data = "new string";
   }
}

edited Dec 11 '17 at 07:46

answered Feb 25 '12 at 09:04

Boris Strandjev

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score 6 · Answer 2 · answered Feb 25 '12 at 09:42

You can initialize a final instance variable after declaration.

If it's static, you have to initialize it in a static initialization block.
Else, you have to initialize it in the constructor.

The problem with the code you've posted is the uppercase C. It should have been class as Boris pointed out.

score 3 · Answer 3 · answered Feb 25 '12 at 10:03

3

It is likely that you are having more than one constructor, in that case you must initialize the final instance field in each of those constructors.

answered Feb 25 '12 at 10:03

Ashwinee K Jha

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score 2 · Answer 4 · answered Feb 25 '12 at 09:59

Like Boris suggested the code is fine. What you can not do though, would be to assign a second value to the final variable data. data = "another string"; will not compile, since data is final and thus its value can not be changed after the initialization.

public class A {
   private final String data;

   public A() {
      data = "new string";
      data = "another string";
   }
}

Is it possible to initialize a final variable after declaring..?

4 Answers4