Casting interface to child interface

Question

How can I cast a interface to the child interface?

Example:

public interface A { ..... }
public interface B extends A { ..... }
... 
A objA = generateA();
B objB = (B) objA; 
...

Have you tried to run your code? What is your problem with it? — McPringle, Oct 16 '21 at 08:22
you will most likely get runtime exception by casting from superclass to subclass unless the class for objA also implements interface B — ProDec, Oct 16 '21 at 08:26

score 1 · Accepted Answer · answered Oct 16 '21 at 08:17

1

What you've done in your example is correct.

ParentInterface objA = new ChildImplementation();
ChildInterface objB = (ChildInterface) objA;

You will get a runtime cast exception if objA is not really of the ChildInterface type.

answered Oct 16 '21 at 08:17

Gonen I

1

I made another type of error. Thanks so much anyway. – Riccardo Oct 16 '21 at 08:24

1 Answers1