java.util.Optional.map code snippet-1

java.util.Optional.map.codesnippet1.java

// Get all notes by userId
java.util.Optional;
java.util.Optional.map()
	
java.util.Optional class
// A container object which may or may not contain a non-null value.
// If a value is present, {@code isPresent()} will return {@code true} and
// {@code get()} will return the value.
	
// Approach-1
Optional<NoteUser> noteUser = noteRepository.findById(userId);
if (noteUser.isPresent()) {
    List<Note> notes = noteUser.get().getNotes();
}
return notes;

// Approach-2
List<Note> notes = noteRepository.findById(userId)
				 .map(NoteUser::getNotes)
				 .orElse(null);
return notes;