Understanding wildcards in Java generics

Question

I\'m not sure why the last statement in the following code is illegal. Integer should be a subtype of ?, so why can\'t I assign it to b

Answer 1

It's because we cannot guarantee that Integer is a subtype of the parameter type "?".

Look this:

Object c = b.get(0);

This is valid, as ? will always be an subtype from Object.