avoid instanceof in Java

Question

I have been told at some stage at university (and have subsequently read in upteen places) that using instanceof should only be used as a \'last resort\'. With this

Answer 1

It is always a bit "fishy" to me to mix objects of different classes in the same Collection. Would it be possible / make sense to split the single Collection of GameObjects into multiple Collections, one of mere GameObjects, another of UITweenables? (e.g. use a MultiMap keyed by a Class). Then you could go something like:

for (UITweenable uit : myMap.get(UITweenable.class)) {
  uit.setUITweenManager(mUITweenManager);
}

Now, you still need an instanceof when you insert into the map, but it's better encapsulated - hidden from the client code who doesn't need to know those details

p.s. I'm not a fanatic about all the SW "rules", but Google "Liskov Substitution Principle".