With the var keyword the variable will be the exact same type as what you initialize it to, not an interface.

  List<Foo> list = new ArrayList<Foo>();

...is programming towards an interface, whereas

  var list = new ArrayList<Foo>();

...isn't, because the type of list will be ArrayList. I think his point was that with the new Java stuff you could instead do

  List<Foo> list = new ArrayList<>();

...which would then be explicitly programming towards an interface, while still not having to type so bleeding much.