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General <strong>Java</strong> Questions III<br />
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General <strong>Java</strong> Questions III<br />
Q: I propose that <strong>Java</strong> should allow multiple inheritance if...<br />
Everyone knows the potential problem with multiple inheritance is when you run into<br />
the problem of having two instances of a grand parent super class.<br />
For example:<br />
class A extends D {int i; }<br />
class B extends D {int i; }<br />
class C extends A,B {}<br />
Potentially, you could have two copies of D for each instance of C.<br />
However, I propose that <strong>Java</strong> should allow multiple inheritance if there are no<br />
instance variables associated with the abstracts that the base class is extending.<br />
abstract class A { public setX(); public setY(); public setAll() {setX (); setY(); }<br />
abstract class B { public setC(); public setD(); public setBoth()<br />
{setC(); setD(); }<br />
class C extends A,B {}<br />
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You won't have two instances of some grandfather class, since A and B doesn't have<br />
instances variables.<br />
I hope the next versions of <strong>Java</strong> explores this issue.<br />
Answer: It does. They're called interfaces:<br />
file:///F|/350_t/350_tips/general_java-III.htm (1 of 9) [2002-02-27 21:18:30]
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