OCP Practice Exams Sef-Assessment Test 2 Q4

[Jeet Jain]

i did not understand the solution to this ques.:

1. public class WeatherTest {
2. static Weather w;
3. public static void main(String[] args) {
4. System.out.print(w.RAINY.count + " " + w.Sunny.count + " ");
5. }
6. }
7. enum Weather {
8. RAINY, Sunny;
9. int count = 0;
10. Weather() {
11. System.out.print("c ");
12. count++;
13. }
14. }

What is the result?
A. c 1 c 1
B. c 1 c 2
C. c c 1 1
D. c c 1 2
E. c c 2 2
F. Compilation fails.
G. An exception is thrown at runtime.

Answer (for Objective 1.1):
 C is correct. All of an enum’s values are initialized at the same time, and an enum’s
variables are treated as if they were instance variables, not static variables.
 A, B, D, E, F, and G are incorrect, based on the above.

[Ankit Garg]

Jeet after compilation enums are changed into actual classes. So your Weather enum after compilation would look like

class Weather extends java.lang.Enum {
  public static final Weather RAINY = new Weather();
  public static final Weather Sunny = new Weather();
  int count = 0;
  Weather() {
    System.out.print("c ");
    count++;
  }
}

[Jeet Jain]

thank you for your reply.Exactly according to your answer the enum constant initialization happens before main() is executed,i.e when the class is loaded at runtime. So printing the count values of the 2 enum constants in main() should print 2 2, not 1 2 as the correct answer says, right?

[Ankit Garg]

should print 2 2, not 1 2 as the correct answer says

Check the answer again, it says 1 1 not 1 2. count is an instance variable not static...

[gihan dissanayaka]

ya this is prints 11.but i don't know count is static or not.
@ankit- why you are saying count is not static

[Jeet Jain]

thank you so much Got it

[Ankit Garg]

Fields declared in an enum are instance fields. This is written in the JLS...

[gihan dissanayaka]

Thank you