Look on interface
public interface Future<V> {//...}
So when you use method that returns you future you can simply put there parameter to be sure what it is returning(it might be also some kind of abstraction). Try to think about how to improve your code that make you to check the instance of returning object or create some interface that can be applyied to your future to be more safe.
public interface SomeInterface{//...}
public Future<SomeInterface> yourMethod(){};
Try to look deeper into architecture of your solution to avoid unchecked sitution and reconsider it, there is always some solution that can by applied to create more safe code.