What is the difference between ArrayList.clear() and ArrayList.removeAll()?

Question

Assuming that arraylist is defined as ArrayList arraylist, is arraylist.removeAll(arraylist) equivalent to arraylist.clear()?

Answer 1

clear() will go through the underlying Array and set each entry to null;

removeAll(collection) will go through the ArrayList checking for collection and remove(Object) it if it exists.

I would imagine that clear() is way faster then removeAll because it's not comparing, etc.