Variable initialization

[Deepali Pate]

public class AQuestion 
    { 
         private int i = giveMeJ(); 
         private int j = 10; 
         private int giveMeJ() 
         { 
              return j; 
         } 
         public static void main(String args[]) 
         { 
              System.out.println((new AQuestion()).i); 
         } 
    } 

Why doesnt this code give compile error that j is not initialized in givemeJ() method.

[Amir Ghahrai]

One possibility may be that the variable j is an instance variable not a local variable, and gets initialized to the default value of 0. Only local variables have to be explicitly initialized before they're used.

[Jose Botella]

JLS 8.3.2.3 explains that. Field access expressions that ocurr whithin a method are not checked for forward references.

[Alan Chong]

class Whatever { int i = 2; }
The above statement in C++ will just reserve a
int variable with an initial value of 2.
But in Java, the above statement reserves a int
variable with a value of 0. After the program
starts, 2 is assigned to i. It is a two-step job.
I got a question like this in JQPlus, and I answered wrong.

[Chung Huang]

Um...could it be because j is an instance variable, and the method is also an instance member and so each object get a copy of j which the object can access. Since j is an instance member, it is initialized to default value of zero.
Correct me if I am wrong.
Let me modify this thing, j was initialized to 10 (or was it 20?). The rest is just that your j inside of the method is interpreted as j of the instance member which does exist, so no complain.
[ June 30, 2002: Message edited by: Chung Huang ]

[Mandar Patki]

Hi All,
I am preaparing for SCJP and I am finding Javaranch very useful for this. Lots of interesting discussions goes on here and help me to grasp the basics of Java. I am really thankful to all my new freinds here. I will try myself to get involve into discussions soon as I am revising my Java concepts.
Thanks once again,
-Mandar Patki

[Jose Botella]

Wellcome to the Ranch Mandar!
Yes it is maybe the best resource in the net for the exam. It also helped me a lot when I took the exam.