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

1import java.util.*;
2class GrindingMachine {
3    String brand;
4    String powerSource;
5    public GrindingMachine(String b, String pS) {
6        this.brand = b;
7        this.powerSource = pS;
8    }
9}
10public class Test {
11    public static void main(String[] args) {
12        var machineList = new ArrayList<GrindingMachine>();
13        machineList.add(new GrindingMachine("Bosch", "Electric"));
14        machineList.add(new GrindingMachine("Hitachi", null));
15        for (GrindingMachine obj : machineList) {
16            Optional<String> op1 = Optional.ofNullable(obj.powerSource);
17            op1.ifPresent(source -> System.out.println(source));
18        }
19    }
20}