If you are sure that the first object in the List always is an Integer, you don't need instanceof.
Use instanceof if you could get different type of objects and want to do different things with them based on their type *and* you can't use
polymorphism to do it.
The soul is dyed the color of its thoughts. Think only on those things that are in line with your principles and can bear the light of day. The content of your character is your choice. Day by day, what you do is who you become. Your integrity is your destiny - it is the light that guides your way. - Heraclitus