Find all implementations of an interface including lambdas

I have a unit test that searches through my project and finds all implementations of a particular interface. Then for each implementation that is an inner class, I assert that it does not capture the outer class.

I use the Reflections library to do this, and it did work, but now I need to test another interface, many of whose implementations are lambdas. Sadly, Reflections cannot find lambda implementations of interfaces.

Is there another library (or solution) I can use that will work with lambdas?