The way that I understand it, this has to do with how the Scala classes are created. In Java, the class defined above would be initializing the variables inline, and since a had not been defined yet, it could not be compiled. However, in Scala it is more the equivalent of this in Java (which should also produce null in the same scenario):
class Omg {
private B b = null;
private A a = null;
Omg(){
b = new B(a);
a = new A();
}
}
Alternately, you could make your declaration of b lazy, which would defer setting the value until it is called (at which time a will have been set).
