Remember that in Java, for a reference variable of some type referring an object of its supertype is forbidden: arrows in Figure 8 must not be directed upwards.

Type erasure in Java generics programming can cause a variety of problems in your code. Fortunately, there are ways to work around them.

Okay, I've got two objects. There's the Hand object, and the Finger object. These are fake. The mappings are correct, I believe, everything works fine usually, I think I'm just misunderstanding ...