Question 12: Method Optional.ofNullable(T value) returns an Optional …

1import java.util.*;
2class HearingAid {
3    String brand;
4    String batteryType;
5
6    public HearingAid(String b, String bt) {
7        this.brand = b;
8        this.batteryType = bt;
9    }
10}
11
12public class Test {
13    public static void main(String[] args) {
14        var aidList = new ArrayList<HearingAid>();
15        aidList.add(new HearingAid("Phonak", "Rechargeable"));
16        aidList.add(new HearingAid("Widex", null));
17
18        for (HearingAid obj : aidList) {
19            Optional<String> op1 = Optional.ofNullable(obj.batteryType);
20            op1.ifPresent(type -> System.out.println(type));
21        }
22    }
23}