Does a method reference in Java 8 have a concrete type and if so, what is it? [duplicate]

Answer 1

Method references are just a syntactic sugar for a function that uses passed parameter as an input argument. So, you can assign them this way:

Runnable runnable = System.out::println;
Consumer consumer = System.out::println;

types are inferred and depend on a context.

Your case:

Function foo = helloGreeter::makeGreetingFor;

and it is equal to:

Function foo = s -> helloGreeter.makeGreetingFor(s);