About Question enthuware.ocajp.i.v7.2.983 :

[DesRenthuware]

Hi

The explanation for this question indicates that an explicit cast is required for both answers. While I can understand the downcast required to assign o to r, I don't think b requires it to be explicit (though it does no harm). As b is a subclass of a and inherits all its interfaces, we should be able to upcast b to r implicitly?

Thanks

[admin]

Yes, you are right. The cast is not really required for option 5. The explanation is valid for option 2 only. This has now been fixed.

thank you for your feedback!