Question

Strange, but I can’t find a duplicate for this question.
I have a superclass with overrideMe() method and a subclass that overrides it.
Is the final field really initialized before the subclass constructor is called?
As I can see from the output, it is.

Here’s the output:
Superclass constr
str value: someValue
Subclass constr
str value: someValue

Could you please explain this to me?
I thought that instance variables are initialized within the constructor call but not before it.

Here’s the code:

public class Test {
  public Test() {
    System.out.println("Superclass constr");
    overrideMe();
  }

  public void overrideMe() {
  }
}

class Ext extends Test {
  private final String str = "someValue";

  public Ext() {
    System.out.println("Subclass constr");
  }

  @Override
  public void overrideMe() {
    System.out.println("str value: " + str);
  }

  public static void main(String[] args) {
    Ext test = new Ext();
    test.overrideMe();
  }
}

EDIT:
if I declasre str field as non-final, the subclass call of it in the constructor returns null as I expect.

Answer 1

Yes fields are initialized before the constructor is called, and this starts with the upper class before the overloading one.

Here’s a general presentation : http://www.linuxtopia.org/online_books/programming_books/thinking_in_java/TIJ306_014.htm