public class Main {
public static void main(String... args) {
Something something = new Something();
Converter<String, String> stringConverter = something::startsWith;
String converted3 = stringConverter.convert("Java");
System.out.println(converted3); // result J
}
}
class Something {
String startsWith(String s) {
return String.valueOf(s.charAt(0));
}
}
@FunctionalInterface
interface Converter<F, T> {
T convert(F from);
}