Please consider the following example,
0..1 sth-- * B;
0..1 sth -- * B;
It generates the following code
public B getB_B(int index)
B aB = (B)bs.get(index);
The variable bs is not accessible in the class D, so there is an error. It's a private varibale in the superclass A.
There several other errors in other APIs in association with the variable bs