Inner classes can't access parent classes in constructor

Question

I'm having a problem where I have class A, which has an Inner class B, which has it's own inner class C. In C's constructor (the inner most class), i'm trying to access a method of A (the top most class), and I get a NullPointerException with trace:
at mearns.finance.DefaultPortfolio.access$0(DefaultPortfolio.java:1)
at mearns.finance.DefaultPortfolio$AccountsEditor$AccountsTableModel.<init>(DefaultPortfolio.java:253)
In this case "DefaultPortfolio" is class A, AccountsEditor is class B, and AccountsTableModel is class C. The line given in the second stack trace element is the line in C's constructor which calls Class A's method.
Debugging, I stop inside C's constructor. Before anything happens, debugger says this$1 is null. Then I step, and it calls super(), and now this$1 is an instance of class B (AccountEditor), but it's own this$1 (which should be an instance of class A) is still null.
I'm calling C's constructor from within B's constructor (but not A's), not sure if that makes a difference.
Can anyone explain what's going on here, and (hopefully) how I can work around it?
Thanks for any help.
When i debug

Answer 1

hm, I really don't know what is happening but I want to tell you about something that is not nice in your code and possibly it could cause the error.
Code behaves somwhat strange when you pass this out of a constructor. You do this implicitly when you create an inner classe which implicitly gets a reference to the outer class. Also just simple method calls can cause such effects.
This is because the construction process it not finished but methods are already called.
Even worse: the sub classes constructor possibly did not even start. Special to java is the fact that a method call can lead to an overridden method of a sub class who's constructors has not even passed the super() command.
My guess now is that you have that some kind of this situation in your code. You create an inner class in a constructor. That inner class calls back a method on the outer class. Now say that the method you are calling is defined in a sub class who's constructor still stucks in super() call. There we are.
I found a thread in a news group that covers exactly this problem:
It is therefore a good idea only to call private methods from constructors (that should then also call only private methods). Also if inner classes are created in the constructor then they should not call any non trivial / non private methods of the outer class. Calling overridden methods out of constructors should be avoided strictly!
Perhaps this has nothing to do with your problem. I cannot tell for sure.
But this sounds quite interesting.
Please tell me if my guess was right and if not post simple code the illustrated your problem.
Here a simple example also throwing NullPointerException:
class Outer {
  int i = 42;
  abstract class InnerSuper {
    InnerSuper() {
      foo();
    abstract void foo();
  class InnerSub extends InnerSuper {
    void foo() {
      System.out.println(i);
  public void bar() {
    new InnerSub();
  public static void main(String[] args) {
    Outer o = new Outer();
    o.bar();
} It causes a NullPointerException because the InnerSub constructor did not run. I copied the example from a news group thread i found.
http://groups.google.de/group/comp.lang.java.programmer/browse_thread/thread/897fba792d689b29/a1ba2ed708636a30?q=inner+class+outer+this+reference+NullPointerException&rnum=4&hl=de#a1ba2ed708636a30
Here is a even simpler example of strange behavior - even without NullPointerExceptions.
class A {
     A() {
          System.out.println(getName());
     String getName() {
          return "A";
class B extends A {
     String NAME = "B";
     String getName() {
          return NAME;
new B();It will output null instead of B.
regards
Sven