Yes, I took the OCP 7 before the OCA 7. (because the beta for the OCP 7 was about to end.) I wouldn't advise this though. The OCP is much harder than the OCA. And you have to circle back and take the OCA anyway.
Ocajp is Oracle Certified Associate Java Programmer.
OCPJP is Oracle Certified Professional Java programmer, that is like lvl2, so, yes
You have to take OCA before OCP