A DESCRIPTION OF THE PROBLEM :
As shown in the sample code, if A.VAR_A is initialized using a method defined in class B, it will be read as null in the static code block in class B. However, if you swap the println statements in the main method, the result is okay.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Execute the sample Java code

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
A
[A, B]
ACTUAL -
A
[null, B]

---------- BEGIN SOURCE ----------
import java.util.*;

public class Main
{
  public static void main (String[]args)
  {
    System.out.println (A.VAR_A);
    System.out.println (B.list);
  }
}

class A
{
  public static final String VAR_A = B.id ("A");
  public static final String VAR_B = "B";
}

class B
{
  public static final List < String > list = new ArrayList <> ();
  static
  {
    list.add (A.VAR_A);
    list.add (A.VAR_B);
  }

  public static String id (String s)
  {
    return s;
  }
}
---------- END SOURCE ----------