Why can I not assign a method reference directly to a variable of Object type?

Question

Simple question about java-8 syntax. Why does JLS-8 restrict such expressions like:

Object of_ref = Stream::of;  // compile-time er         


        

Answer 1

I suspect this is a purely academical question, since I can't see any real-life use case for this. Nevertheless, I am pretty sure that it has to do with Stream::of being a lambda expression. You could also not do this:

Object of_ref = list -> Stream.of(list);

I speculate that an accurate return type tells the compiler which FunctionalInterface it being used. Without this information it is impossible for the compiler to resolve the Lambda expression correctly and unambiguously.