Java Optional check if there is a value in Optional

import java.util.Optional;

public class Main {
  public static void main(String[] args) {
    Optional<String> str = Optional.of("your value");

    if (str.isPresent()) {
      String value = str.get();//ww w  . j  a v a 2  s .  co m
      System.out.println("Optional contains " + value);
    } else {
      System.out.println("Optional is  empty.");
    }
    String o = null;
    str = Optional.ofNullable(o);
    if (str.isPresent()) {
      String value = str.get();
      System.out.println("Optional contains " + value);
    } else {
      System.out.println("Optional is empty.");
    }

  }
}

import java.util.Optional;

public class Main {
  public static void main(String[] args) {
    Optional<String> str = Optional.of("AAA");

    str.ifPresent(value -> System.out.println("Optional contains " + value));
    //from   www  .  j a  v a  2s .co  m

    String o = null;
    str = Optional.ofNullable(o);
    str.ifPresent(value -> System.out.println("Optional contains " + value));
    
  }
}