Your example shows why it is not recommended to hide fields. It makes
code that is hard to read and understand. In this case access to the
field 'r' is based upon the reference type not the object type.
Also the method call to a.xx(); doesn't have an actual method defined
for it so the code will not compile with that line there.
I think it is poor practice to assign initial values to fields outside
of a constructor (unless they are static or final fields).
On 13/01/2010, at 8:05 AM, nn roh wrote:
Hi,
why in this examples the variable r which is in parent used ?
class Q16
{
public static void main(String args[])
{
A a = new B();
a.callme();
System.out.println(a.r);
a.xx();
}
}
class A
{
void callme()
{
System.out.println("A");
}
int r=10;
}
class B extends A
{
public void callme()
{
System.out.println("B");
}
int r=20;
}
output :
B
10
Thanks,
On Sun, Jan 3, 2010 at 8:55 PM, SAADELDIN SULIMAN <[email protected]
> wrote:
superclass classname=new subclass()
there is inheritance
Please read about inheritance.
thanks
Suliman
On Sat, Jan 2, 2010 at 1:01 PM, nn roh <[email protected]> wrote:
> What is the difference if we define the class as
>
> superclass classname=new subclass()
>
> subclass classname=new subclass()
>
>
> Thanks;
> Nada
>
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