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mULTIPLE iNHERTANCE FOR mEMBER TYPES IN iNTERFACES jAVA

hI ,

Iam trying to implement the issues we get when we inherit two interfaces with same member type name , I should get the member type name ambiguity error , but not getting it. Any help is really appreciated.

public interface Bank
{
      interface Card
      {
            String getCardType();
      }
}

public interface ATM
{
      boolean login (int acctno);
      interface Card
            {
                  double getamt(int acctNo);
            }
}

public interface DummyBank extends ATM, BANK
{
int getChequeDepositedDetails(int acctno);
}

-- Should produce an error for member type name when compiled ambiguity , but not getting it.
public class SBIBankImpl implements DummyBank
{

public String getCardType()
{
return "SBI DEBIT CARD";
}

public boolean login (int acctno)
{
return true;
}

public double getamt(int acctNo)
{
return 10000.03;
}

public int getChequeDepositedDetails(int acctno)
{
return 1233444444;
}

public static void main (String [] args)
{
SBIBankImpl c = new SBIBankImpl();
String name=c.getCardType();

System.out.println(name);

}
}

CPColin

I'm pretty sure you get the error for non-static members only. Nested interfaces are static, so there's no problem.

Swaminathan K

ASKER

Hi

We will get an error when we have two interfaces with member types with same name even though they are static or non static , I should get ambiguity error.

Swaminathan K

ASKER

public interface Bank
{
int Yes=1;

}

public interface ATM
{
int Yes=2;

}

public interface DummyBank extends ATM, BANK
{
int ans=Yes;
}

Throws as ambiguity error telling which interface constant value to use. Similar to this I should get an error for member types in Interface.

CPColin

Well, sure, in that example, the compiler has no way of knowing whether you mean Bank.Yes or ATM.yes. In your first example, you're not making any references to Bank.Card or ATM.Card, so there's no problem.

Swaminathan K

ASKER

Yes, I need an example which will throw an error for the member types , any help in this regard is really appreciated .

CPColin

interface A
{
   default int getValue()
   {
      return 0;
   }
}

interface B
{
   default int getValue()
   {
      return 1;
   }
}

class AB implements A, B
{
   // This produces an error because the compiler can't tell if you want
   // A.getValue() or B.getValue() to run when somebody calls AB.getValue().
}

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Swaminathan K

ASKER

I want the example with either Nested Interface or Nested Classes name collision

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mccarl

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CPColin

I want the example with either Nested Interface or Nested Classes name collision

I can't think of one. It seems unlikely to happen in real code.

Swaminathan K

ASKER

public class CardImpl implements DummyBank.Card {
}

Iam not getting the error , its says cannot find the symbol.

mccarl

Have you got that in a different package or anything like that ? Also what version of Java are you compiling with?

Swaminathan K

ASKER

Java 1.8 version

mccarl

Hmmm, not sure then. Can you post the full error? Maybe a screenshot so we know exactly what it is referring to, etc?

Swaminathan K

ASKER

Sorry , I tried to implement the same and it worked.