Although I think the presentation went quite well, one of the glaring mistakes that I made was about how to test the functional features exposed in JDK 1.8. I said in the presentation, "If you are going to write a unit test for a functional program, you’re going to focus on the smallest possible units within it, and you might not get to point of actually invoking a function. When you write unit tests, start with the smallest part first, and then work your way up."
What was I saying? I can honestly say that I messed up in a live presentation there. Sorry.
What I should have said was that a unit test typically focus on the results of a method, where as a a lambda expression or even the use of method reference are parts of code that happen within a method. Although it is possible to copy and paste snippets of code for specific purpose of writing a unit test for it, is probably better to as tightly as possible wrap the part of code that uses lambda expressions and method references with a method so that it also can be unit tested. It will also be quite possible to use mocking where possible.