Very nice presentation. However much of this can be actually discovered and felt first hand just by playing with profilers that support memory profiling (such as yourkit[1]).
After a few hours playing with it, you will never forget the precious lessons on this presentation.
Per object overhead in functional languages is usually lower since polymorphism is handled at the function level rather than the data level. You don't have to store class pointers etc, just the raw data and probably a type tag.
For those of you who may not be familiar with them, using http://fastutil.dsi.unimi.it/ collections instead of Java collections is essentially the work-around for most things you'll use. Fastutil has custom classes that remove the pointer overhead associated with storing primitives. Unfortunately, Java really falls apart at the primitives aren't objects thing when it comes to performance.
Some (not all) of these cases would be helped massively if the JVM gained an equivalent of the fixnum/flonum types from the LISP world. This has been proposed kind-of seriously in the past, e.g.:
After a few hours playing with it, you will never forget the precious lessons on this presentation.
[1] http://www.yourkit.com/