Application1.java

import java.util.Optional;
import java.util.function.Consumer;

public class Application1 {
  public static void main (String[] args) {
    let(new ArrayWrapper<String>(args), a ->{
      System.out.println(fullName(a.get(0), a.get(1)).orElse("Failure"));
    });
  }

  public static Optional<String> fullName(Optional<String> firstName, Optional<String> familyName){
    return firstName.flatMap( first -> familyName.map( family -> String.format("%s %s",first, family)));
  }

  static <T> void let(T obj, Consumer<T> body){
    body.accept(obj);
  }
}

class ArrayWrapper<T>{
  private T[] array;
  public ArrayWrapper(T[] array){
    this.array = array;
  }

  public Optional<T> get(int index){
    try{
      return Optional.of(array[index]);
    }catch(ArrayIndexOutOfBoundsException e){
      return Optional.empty();
    }
  }
}

// Results:
// $ java Application1 John
// Failure
// $ java Application1 John Doe
// John Doe