class A
{
}
class B extend A
{
int i;
int j;
}
Can a class have an IS-A Relationship with itself?
In this question, B is an A, right?
But can class B have an IS-A relationship with class B?
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7Are you asking if, for example, a dog **is a** dog? – Sotirios Delimanolis Sep 20 '14 at 04:37
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Take a look at http://stackoverflow.com/questions/4584541/check-if-a-class-is-subclass-of-another-class-in-java – user3885927 Sep 20 '14 at 04:39
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Yes same question is asked in my ocjp exam.. – Amit2311 Sep 20 '14 at 04:40
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1Are you sure that's what it asks? _is a relationship_ isn't a technical term. I would think OCJP deals with technical Java Language concepts. – Sotirios Delimanolis Sep 20 '14 at 04:43
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Is a tautology true? This question doesn't lead anywhere. There is no truth left to be discovered. I think you may have misunderstood what they were asking. A question that would take you somewhere is: A extends B, B is a A, Can it be possible that A is a B? – Mikeologist Sep 20 '14 at 04:57
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It's *like* asking yourself if you are yourself. – lxcky Sep 20 '14 at 05:01
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it depends on what the meaning of *is* is. – drew moore Sep 20 '14 at 05:50
1 Answers
1
It's an identity (and tautology) - an object of type B will always be able to describe itself as an object of type B.
The further extensions of the is-a relationship pertain to hierarchies of inheritance; that is to say, since B extends A, B is-an A. This allows you to write the following expression:
A anA = new B();
But B is a B too. It hasn't lost that part of its identity because it now inherits from another class.
Makoto
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