enum doubt

[raja kanak]

import java.util.*;
 
enum Colours {
YELLOW (Personality.EXPRESSIVE),
GREEN (Personality.AMIABLE),
RED (Personality.ASSERTIVE),
BLUE (Personality.ANALYTICAL);
 
Personality personality;
 
Colours (Personality personality) {
this.personality = personality;
}
 
enum Personality {ASSERTIVE, EXPRESSIVE, AMIABLE, ANALYTICAL };
}
 
class TestColours {
public static void main (String[] args) {
// INSERT LINE OF CODE HERE
}
}
 
Which line of code when replaced with "// INSERT LINE OF CODE HERE", will output a value "true":
 
    * a) System.out.println (Colours.Personality.ASSERTIVE instanceof Colours.Personality);
    * b) System.out.println (Personality.EXPRESSIVE instanceof Personality);
    * c) System.out.println (EXPRESSIVE instanceof Personality);
    * d) None of the above 

The answer, the mock exam says is (a).
Why not b & c. Please explain

[Barry Gaunt]

Have you tried the other two options when you compiled and ran the program? What error messages or results did you get? Please show some effort in solving the problem.

From what mock exam did you get this question?

[Sanjeev Singh]

Raja,
Here is the clue : All nested class are implicitly final(unless atleast one constant has a class body) and static.

[raja kanak]

I got this question from
http://www.ejavaguru.com/scjp5freemockexam.php (8th question)

While compiling, I got the error message
"cannot find symbol"

that means, Personality cannot be accessed directly; it can be assessed through Colours.(Like inner class) Am i right?

[Sanjeev Singh]

that means, Personality cannot be accessed directly; it can be assessed through Colours.(Like inner class) Am i right?

comiler changes the enums into class something similar to this.

final class Colours extends Enum
{
    static final class Personality extends Enum
    {
    }
}

[ November 23, 2006: Message edited by: Sanjeev Kumar Singh ]

[Barry Gaunt]

As Sanjeev pointed out, Personality is a static nested enum of Colours, so to access it from outside Colours you must use Colours.Personality and Colours.Personality.EXPRESSIVE.

[megha joshi]

Quote: "All nested class are implicitly final(unless atleast one constant has a class body)"

I think the above all is only in the context of Enum's inner classes. Also I didnt get "unless atleast one constant has a class body".

Thanks in advance for helping.

[Keith Lynn]

An enum type is implicitly final unless one of the constants has a constant-specific class body.

In this case the constant-specific class body defines an anonymous subclass of the enum type.

Enums