//version 8: import java.util.function.Consumer; import java.util.function.Function; import lombok.experimental.ExtensionMethod; @ExtensionMethod({ExtensionMethodAmbiguousFunctional.Extensions.class}) class ExtensionMethodAmbiguousFunctional { public void test() { "".ambiguous(System.out::println); } static class Extensions { public static void ambiguous(T t, Function function) { } public static void ambiguous(T t, Consumer function) { } } }