protected modifier

[Ashwin Sharma]

hi all,
When you inherit some class(It has the protected variable) in same package, instance of sub class is able to access protected variable of other instance of same class.
But if you inherit the class in other package, instance of sub class is unable to access protected variable of other instance of same class.
Why is this so?

[Burkhard Hassel]

Hi ranchers,


Ashwin Sharma posted November 13, 2006 01:51 AM

But if you inherit the class in other package, instance of sub class is unable to access protected variable of other instance of same class.

There should be no problem with instances of the same class extending the class with the protected member.

But the protected members are invisible in other classes extending the same class with the protected member.

e.g.
one file:

package tests.pack1;
//            ======
public class ProtectedDemo {
protected String protectedString="protected";
}

other file:

package tests.pack1.subpack;
//                  =======
 
import tests.pack1.ProtectedDemo;
 
public class SubClass extends ProtectedDemo {
public static void main(String[] args) {
SubClass one = new SubClass();
SubClass two = new SubClass();
one.protectedString = two.protectedString;   // A
 
AnotherSubClass other = new AnotherSubClass();
one.protectedString = other.protectedString; // B
}
}
 
class AnotherSubClass extends ProtectedDemo{ }
 

Therefore line A will compile, line B will not (protectedString not visible).


Yours,
Bu.
[ November 13, 2006: Message edited by: Burkhard Hassel ]

[Ashwin Sharma]

hi Burkhard,

May be i was'nt able to explain my doubt more clearly. So let me explain it again-
package pac1;
class Super
{
protected int a;
}

package pac1;
class Sub
{
public int b;
void method()
{
Sub s = new Sub();
b = s.b;
}
}

// the above will work.

package pac1;
class Super
{
protected int a;
}

package pac2;
class Sub
{
public int b;
void method()
{
Sub s = new Sub();
b = s.b;
}
}
// this code will not work.
Access specifier works at class level, so why does it shows this type of behaviour at the instance level.

[Jesper de Jong]

Ashwin!

Please do not post the same question in multiple forums!