sendError qn in j2eecertificate

[Sundar Murthi]

I am attended the following qn in j2eecertificate demo exam.
What is the answer for this qn.

Which of the following statements regarding the sendError response method are true? [Check all correct answers]

1. sendError accepts java.lang.Throwable as an argument.
2. sendError can throw java.lang.IllegalStateException.
3. sendError has the side effect of committing the response.
4. sendError is only used to set the return status code when there is no error.
5. sendError throws an java.lang.InvalidStateException if the response has already been committed.

the answer given is 2 3 how it is?

[Nitish Bahadur]

Refer to the HttpServletResponse.sendError(...) documentation in the spec.

"If the response has already been committed, this method throws an Illegal-
StateException. After using this method, the response should be considered
to be committed and should not be written to."