Chaining Optional (Java 9 Optional#or)

ChainingOptional.java

import java.util.Optional;

class ChainingOptional {

  static Optional<Integer> get1() {
    return Optional.empty();
  }

  static Optional<Integer> get2() {
    return Optional.empty();
  }

  static Optional<Integer> get3() {
    return Optional.of(3);
  }

  public static void main(String[] args) {
    var integer = get1().or(() -> get2()).or(() -> get3()).orElseThrow();

    System.out.println(integer); // 3
  }
}