I was just thinking about it as I was walking home from the station. What if a sentient alien race with the same level of technology as current humans, came into direct contact with the human race?

1. Would the aliens see humans as inherently violent (non-stop war, basically enslaving all other earth-organisms), or inherently peaceful (we haven't destroyed ourselves using nuclear weapons yet)?
2. Would humans and the aliens interact with each other if there is the possibility of significantly bettering the technology for both races (i.e both sides have much to gain by cooperating)? Or would humans and aliens be naturally suspicious of each other and ditch that idea? Or have a war (which would be dehabilitating for both sides)?

a) If humans had a war with aliens, would ll of humanity be able to unite as one entity to fight the aliens? Or would humanity still be divided over their own petty quarrels?