W3School TIY Editor

public class Main {

  public static void main(String[] args) {

    StringFunction exclaim = (s) -> s + "!";

    StringFunction ask = (s) -> s + "?";

    printFormatted("Hello", exclaim);

    printFormatted("Hello", ask);

  }

  public static void printFormatted(String str, StringFunction format) {

    String result = format.run(str);

    System.out.println(result);

  }

}

​

interface StringFunction {

  String run(String str);

}

​