I've decided to be java certified we all know that OCJA7 or OCJP6 are pre-request for OCJP7
So I need to decide which cert are better to start with but I need to consider that there will be a gab between the first exam and second one about 4 months
Is to get OCJP6 then upgrade it to OCJP7 better or to Start from OCJA7 ?
It really depends on your level of java knowledge and what you intend to do. I assume you are a software developer.
OCA (Oracle Certified Associate) is a really basic entry exam. From my experience in Germany, employees usually don't care about it.
OCJP (Oracle Certified Java Professional) shows that a developer has some knowledge of Java. Employees (again in Germany) actually know about and this certificate might help you to get a job offer. There are a lot of rather bizarre questions asked during OCJP, so it's a really good idea to study OCJP preparation materials.
Now, when it comes to versions, I think employees don't care too much about it. You could have OCJP6 or OCJP7 but that won't matter too much. Your actual work experience will count a lot more than the OCJP version. That said, having a really old OCJP certificate might not be perceived so well. Updating your OCJP certificate once in 3-5 years should be enough for the most employees.