Enthuware

K is a valid interface because an interface is permitted to extend another interface.

When interface K intends J, doesn't K need to override all the methods in J? When overriding the method getJ(), is it allowed to modify the method parameter?

No, an interface doesn't implement anything so there is no question of overriding.
If you change the method parameters, then it is not overriding anyway. It is overloading.

HTH,
Paul.

I answered that "It will fail to compile because of MyIJ"
which is defined as :

abstract class MyIJ implements J , I { }

When I enter that definition in Eclipse, I get the error message that an Abstract class cannot have a body.

Why isn't this the correct answer?

Can't really comment on what Eclipse (or any other IDE) says and does. Please try it on command line with regular javac command.

BTW, we do not recommend the usage of any IDE while preparing for this exam.

HTH,
Paul.