help!

[PETER CARTER]

package test1;
public class Test1 {
static int x = 42;
}
package test2;
public class Test2 extends test1.Test1 {
public static void main(String[] args) {
System.out.println(�x = � + x);
}
}

A. x = 0
B. x = 42
C. Compilation fails because of an error in line 2 of class Test2.
D. Compilation fails because of an error in line 3 of class Test1.
E. Compilation fails because of an error in line 4 of class Test2.
Answer: C

Why not B? Would you tell me the two packages' relation?
Thanks !

[Jay Pawar]

Peter,
I guess import test1.Test1 statement is needed on line 2.

public class Test2 extends test1.Test1
Here Test1 java class is in different package test1 which is not visible in package test2.
Hope that helps !!!

[Louie van Bommel]

Originally posted by Jay Pawar:
Peter,
I guess import test1.Test1 statement is needed on line 2.

Nope


The class name is fully qualified therefore an import statement would just be redundant.

The correct answer is E.

...
3. static int x = 42;
4. }
1. package test2;
2. public class Test2 extends test1.Test1 {
3. public static void main(String[] args) {
4. System.out.println(“x = “ + x);
...
E. Compilation fails because of an error in line 4 of class Test2.

The compilation fails because x has "package" (also known as default) access and therefore is not accessible to the Test2 class which is in another package.

[Jay Pawar]

You are correct Louie. I didn't see that test1.Test1

[PETER CARTER]

I know a little of your thinking and chang it :
package test1;
public class Test1 {
static int x = 42;
}
package test2;
import test1;//I added.
public class Test2 extends test1.Test1 {
public static void main(String[] args) {
System.out.println(�x = � + x);
}
}

I chang it above ,is it right now ?

[PETER CARTER]

I think the real answer is C and E.
Do you follow me ?

[Barry Gaunt]

To get this to compile you must give protected or public access to the static variable x:

package test1;
public class Test1 {
   [B]protected[/B] /* or [B]public[/B] */ static int x = 42;
}

package test2;
public class Test2 extends test1.Test1 {
    public static void main(String[] args) {
        System.out.println(�x = � + x);
    }
}
  

So the answer to the original question should be:

D. Compilation fails because of an error in line 3 of class Test1.

provided you count from the package statement in the file containing class Test1. Line 3 of class Test1 is where the error (or mistake) is.
[ September 08, 2004: Message edited by: Barry Gaunt ]

[PETER CARTER]

class Test1 {
static int x = 42;
}
public class Test2 extends Test1 {
public static void main(String[] args) {
System.out.println("x = " + x);
}
}
It can complie the answer :
x = 42

[Barry Gaunt]

Now everything is in the same (default) package!