Performance wise, is there really a big difference between using:

* ArrayList.contains(o) vs foreach|iterator
* LinkedList.contains(o) vs foreach|iterator

Of course, for the foreach|iterator loops, I'll have to explicitly compare the methods and return true or false accordingly.

The object I'm comparing is an object where `equals()` and `hashcode()` are both properly overridden.

**EDIT:** Don't need to know about containsValue after all, sorry about that. And yes, I'm stupid... I realized how stupid my question was about containsKey vs foreach, nevermind about that, I don't know what I was thinking. I basically want to know about the ones above (edited out the others).