What programming restrictions are defined in the EJB specifications?

What programming restrictions are defined in the EJB specifications?
1,An enterprise bean must NOT attempt to listen on a socket.
2,A session bean class must NOT have any superclasses and/or superinterfaces.
3,An enterprise bean can directly read a file descriptor.
4,An entity bean class need NOT implement a public zero-argument constructor.

I think the answer is 1,am i correct?

I also think that 1. is the correct answer (compare core spec 21.1.2).

Don't forget to quote your sources.

I also think so. But the question seems bit doubtful. See the option 3. Its not abt a restriction.

1. is correct. It's good to remember this question

It's good to remember this question

Was it part of your exam, Tomaszz ? (just a rhetoric question). I see you passed it with a great score. Congrats! Share your experiences with us.

Well, I had basic knowledge of EJBs, so I didn't used books, only specs (I read them twice and used many times to find answers). I also read many posts from this forum (even the old ones) and I think it is very helpful. Personally I think that SCBCD was the easiest exam (as compared to SCJP and SCWCD).

Along with answer 1. The answer 3 is also correct.
As the session beans should never attempt to read a file descriptor.
I think reading the file descriptor is equivalent to using the FileOutputStream only.

Hi Amandeep,

Yes I agree to you. but it says "An enterprise bean can directly read a file descriptor." not "Can NOT". Its not a restriction. Thats why I said question is bit doubtful.

any way in real exam, they have highlighted special cases using upper cases. for example "An enterprise bean CAN directly read a file descriptor."

Tomaszz, I agree you. I think JP was the hardest exam to me than both WCD and BCD.