SCJP doubt

Hai,
I am planning to appear for Sun Certification and I have joined new in this forum. Let me have those advantages of clear concepts.
Thanks.
Question 1.
Which of the following statements are valid for a method which overrides the foll:
protected void method(int x) {..}
a. overiding method takes int as only parameter.
b. Overriding method must return a void.
c.overriding method can be declared as private.
d.overiding method can return any value it wishes.
Kindly clear my doubt as I have chosen a,b. Is that true?
Quetion 2:
Is -0.0 different from 0.0?
In that case what would be the right answer for ceil() and floor() of -0.5? Kindly clear my doubt.

I'm moving this to Programmer Certification, as this forum is only intended for mock exam questions that are known to be in error.