dear Brown and steve,
thank you for your replies. you have come nearer to my question to some extent.
what i have understood from both of you is that
{
abstract classes - partial implementation
interfaces - No implementation at all
using interfaces we achieve multiple inheritance
}
in both the classes (interface or abstract class), we can not create instances at all. so we are not at all going to use those partial implementation at all.ie no method calls of those partial implementation.
coming to multiple inheritance, sometimes the final derived class may have two or more copies of the same signature from its parent classes. i have enclosed the example coding.
interface A
{
int add(int a,int b);
}
interface B extends A
{
int subtract(int a,int b);
}
interface C extends A
{
int multiply(int a,int b);
}
class D implements B,C
{
public int add(int a,int b) { return a+b;}
public int subtract(int a,int b) {return a-b;}
public int multiply(int a,int b) {return a*b;}
}
class Try1
{
public static void main(
String args[])
{
D d=new D();
System.out.println(d.add(3,4));
System.out.println(d.subtract(4,5));
System.out.println(d.multiply(6,7));
}
}
so in class D, which copy of add() method we are implementing either from B or C, we don't know.
it is avoided in c++, defining the class as virtual at the time of deriving.
it is avoided in java using interfaces without the programmer's knowledge.
so my final
word is that
{
1.parial implementation or no implementation is not at all a matter.
2.multiple inheritance can be achieved by both if sun java developers has already thoght of it. so we can not accept that interfaces in java are only for multiple inheritance.
}
so my question is that
1. has java unnecessarily used two terms which confuses programmers.
2.assuming sun java developers are much more intelligent people than us, what is the exact intension behind in it?
expecting your replies
with regards
balraj