java 8 lambda ambiguous runnable and callback [duplicate]

Question

Executors.newFixedThreadPool(3).submit(() -> {doSmth();});

"Ambiguous method call. Both submit (Callable) in ExecutorService and submit (Runnable) in ExecutorService match."

How to fix it? I know that I can use anonymous class but I'd like to use Function.

Answer 1

Executors.newFixedThreadPool(3).submit(() -> 1); //Callable
Executors.newFixedThreadPool(3).submit(() -> {doSmth();}); //Runnable