// streams/CreatingOptionals.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.*;

import java.util.stream.*;

import java.util.function.*;

class CreatingOptionals {

static void

test(String testName, Optional<String> opt) {

System.out.println(" === " + testName + " === ");

System.out.println(opt.orElse("Null"));

}

public static void main(String[] args) {

test("empty", Optional.empty());

test("of", Optional.of("Howdy"));

try {

test("of", Optional.of(null));

} catch(Exception e) {

System.out.println(e);

}

test("ofNullable", Optional.ofNullable("Hi"));

test("ofNullable", Optional.ofNullable(null));

}

}

/* Output:

=== empty ===

Null

=== of ===

Howdy

java.lang.NullPointerException

=== ofNullable ===

Hi

=== ofNullable ===

Null

*/