import java.util.List; import java.util.function.Function; class Test { { transform(1, (String l) -> null); } public static <I, O> void transform(int input, Function<I, O> function) { System.out.println(input); System.out.println(function); } interface IFunction<F, T> { List<T> apply(F var1); } public static <I, O> void transform(int input, IFunction<I, O> function) { System.out.println(input); System.out.println(function); } }