Question

Can any body explain this generic vector Vector<? super Object> list = ... and where to use it?

Answer 1

Here you are defining the lower bound of your unknown object ?. So the Vector<? super Object can contain only Object and any super class of Object. But since Object does’nt have a super class it has no sense. It behaves same as Vector<Object>.

Refer this sample.

The counterpart for this is upper bound Vector<? extends Object> where you can add any object that extends Object.

You should be able to avoid using Object as the generic type is most cases.