If you want to be an OCPJP7,
you should not take this certification but the OCAJP7. You could also decide to take OCPJP6 first (using the famous K&B book) and then upgrade to OCPJP7. That's up to you.
The OCAJ 5/6 is not intended for
java programmers/developers, but more for non-technical people (like managers).