Since Java 9, it’s possible to use Optional with a stream in case we need to manipulate values from a List. In this Java Challenge, we will explore the use of a stream in an Optional! Are you ready to solve this Java Challenge?
[qsm quiz=22]
If you want to watch the FULL video explanation, check this out: (Before, try out the Java Challenge on your own)
This is it, keep breaking your limits and never stop improving your skills!
Hi Rafael,
I am curios to know what if we have List and some of element of list is null.
How to make use of Stream.ofNullable in this case to check null element?
List sopranoList = new ArrayList();
Collections.addAll(sopranoList, null, new Soprano(List.of(“hi”, “hello”)));
Got it.
List sopranoList = new ArrayList();
Collections.addAll(sopranoList, null, new Soprano(List.of(“hi”, “hello”, “bye”)));
/** */
sopranoList.stream()
.flatMap(e -> Stream.ofNullable(e)) //empty or Stream of single element sopnaro
.flatMap(e -> Stream.of(e.list)) //Stream of list of string
.flatMap(s -> s.stream()) //Stream of string
.filter(ele -> ele.equals(“hello”))
.forEach(System.out::println);