aspose file tools*
The moose likes Programmer Certification (SCJP/OCPJP) and the fly likes protected access modifier Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login


Win a copy of Spring in Action this week in the Spring forum!
JavaRanch » Java Forums » Certification » Programmer Certification (SCJP/OCPJP)
Bookmark "protected access modifier" Watch "protected access modifier" New topic
Author

protected access modifier

Puja S
Ranch Hand

Joined: Jan 06, 2005
Posts: 51
Hi,

package testpkg.p1;
public class ParentUtil {
public int x = 420;
protected int doStuff() { return x; }
}

package testpkg.p2;
import testpkg.p1.ParentUtil;
public class ChildUtil extends ParentUtil {
public static void main(String [] args) {
new ChildUtil().callStuff();
}
void callStuff() {
System.out.print("this " + this.doStuff() );
ParentUtil p = new ParentUtil();
System.out.print(" parent " + p.doStuff() );
}
}

which statement is true?

1. The code compiles and runs, with output this 420 parent 420.

2.If line 8 is removed, the code will compile and run.

3.If line 10 is removed, the code will compile and run.

4.Both lines 8 and 10 must be removed for the code to compile.

5.An exception is thrown at runtime.


The answer ios 3....Why? Can anybody explain me. I thought the answer was 1.

Thanks.
Mike Gershman
Ranch Hand

Joined: Mar 13, 2004
Posts: 1272
In order to acess a protected member of a superclass that is in another package, you must use a reference type of your class or a subclass of your class. So this was OK, because it is of type ChildUtil, but p is not OK because it is of type ParentUtil.


Mike Gershman
SCJP 1.4, SCWCD in process
Puja S
Ranch Hand

Joined: Jan 06, 2005
Posts: 51
Thanks Mike,
You said "You must use a reference of your class or a subclass of your class to access the protected member".......I am not able to understand how a subclass of the class can be used.Please can you give me an example.

Thanks
Puja S
Ranch Hand

Joined: Jan 06, 2005
Posts: 51
Thanks Mike........I understood the concept.
meena latha
Ranch Hand

Joined: Jan 24, 2005
Posts: 219
Hi ............i am clear about the concept can any one of you please explain to me.
 
I agree. Here's the link: http://aspose.com/file-tools
 
subject: protected access modifier