Order of Object Creation

Question

I need to know what order various objects are created and processed. An example will be most helpful.
class A {
A() { myFunc();    }
public void myFunc() {}
class B extends A {
class innerB {       public void funcInnerB() { ... do some work ...       } }
public void myFunc() {       someVar.funcInnerB();   }
innerB someVar = new innerB();
When class B is instantiated the following happens [assuming I coded my example properly :) ]
1. The default B constructor is called.
2. It calls the A constructor.
3. The method myFunc in class B is called from A constructor.
4. a NULL Pointer error occurs because someVar has appearantly not yet been assigned to the new innerB object.
This is my problem, why is someVar not being created immediately? I don't know if this problem is universal, but in my particular application, it is happening this way. (I can't post the actual code, because it is way, way too long.)
I tried using an initialization block in class B to assign someVar, but the same problem occurs.
Here's my current workaround:
in class B:
public void myFunc() {  if (someVar == null) { someVar = new innerB() }
someVar.funcInnerB(); }
But I am hoping there is a better solution and I am worried about when I may run into this situation. So, I am hoping there is a definitive guide to the order everything is created.
Thanks in advance.

Answer 1

It's not a good idea to call non-final methods from a non-final class because of exactly what you found. The NullPointerException happens because of the order of processing that you described - by the time you get to B.myFunc(), the B members have not been initialized. First, the superclass is fully initialized. All members are set to their initial values, then the constructor is executed. After the superclass constructor finishes, then the subclass members are initialized, and any further subclass constructor processing occurs.