// functional/ProduceFunction.java
// (c)2017 MindView LLC: see Copyright.txt
// We make no guarantees that this code is fit for any purpose.
// Visit http://OnJava8.com for more book information.
import java.util.function.*;

interface
FuncSS extends Function<String, String> {} // [1]

public class ProduceFunction {
 static FuncSS produce() {
 return s -> s.toLowerCase(); // [2]
 }
 public static void main(String[] args) {
 FuncSS f = produce();
 System.out.println(f.apply("YELLING"));
 }
}
/* Output:
yelling
*/