Hi Ernesto,
Welcome to coderanch!
In old days,
SCJA was not a requirement for
SCJP. Reason was, SCJA mostly dealt with OO concepts than
Java programming.
But now, for JDK7, things have changed. Now OCAJP7 deals with basic Java programming (declaration and usage of basic classes, loop constructs etc.). Secondly, OCPJP7 deals with few more things than SCJP6 (or OCPJP6). Those new additions(NIO package, concurrency pacakge etc.)
were part of JDK6, but were not part of JDK6 certification. Getting knowledge of these things is a good thing (even better : getting approval of Oracle for it
). e.g. working knowledge of java.util.concurrent will save you lot of trouble than using traditional wait/notify approach in OCMJD (or in real life coding).
So, yes, I would suggest that if money is not a problem, please put those extra efforts and get both OCAJP7 and OCPJP7.
Regarding unavailability of OCPJP7 book, check
this.
I hope this helps.
All the best!