This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Every question can be answered by the person who developed the code.
Having said that, the questions can be slightly tricky. I got one question on my essay that asked me to describe something that I didn't use, so my response was exactly that: I didn't use 'x', I used 'y' instead. I can imagine that this would confuse anyone who had a superficial understanding of another persons assignment, as they would try to justify their use of something they didn't use.