Mockito isA(Class<T> clazz) How to resolve type safety?

There is no way to do this. To simplify, you can't initialize this variable without warning :

Class<Iterable<Integer>> iterableIntegerClass = ?

One solution might be to use the pseudo-typedef antipattern, ,you create and use an IntegerIterable interface

interface IntegerIterable extends Iterable<Integer> {}

then

isA(IntegerIterable.class)

will no more produce warning. But you will have to extend the class implementing Iterable to let them implements IntegerIterable :) For example :

public class IntegerArrayList extends ArrayList<Integer> implements IntegerIterable {}

Mmm tasty...

So, i will sugest you to consider to just paper over the cracks by adding to your method :

@SuppressWarnings("unchecked")