Why do this() and super() have to be the first statement in a constructor?

The parent class’ constructor needs to be called before the subclass’ constructor. This will ensure that if you call any methods on the parent class in your constructor, the parent class has already been set up correctly.

What you are trying to do, pass args to the super constructor is perfectly legal, you just need to construct those args inline as you are doing, or pass them in to your constructor and then pass them to super:

public MySubClassB extends MyClass {
        public MySubClassB(Object[] myArray) {
                super(myArray);
        }
}

If the compiler did not enforce this you could do this:

public MySubClassB extends MyClass {
        public MySubClassB(Object[] myArray) {
                someMethodOnSuper(); //ERROR super not yet constructed
                super(myArray);
        }
}

In cases where a parent class has a default constructor the call to super is inserted for you automatically by the compiler. Since every class in Java inherits from Object, objects constructor must be called somehow and it must be executed first. The automatic insertion of super() by the compiler allows this. Enforcing super to appear first, enforces that constructor bodies are executed in the correct order which would be: Object -> Parent -> Child -> ChildOfChild -> SoOnSoForth