Dear Marco Antonio,
The new OCA Java certification (for Java SE 7) is totally different from the old Oracle Certified Associate Java exam.
OCAJ 5/6 (old)
[Java SE, Java ME and Java EE Basic Skills Required]
Oracle Certified Associate, Java SE 5/SE 6 (Formerly Sun Certified Java Associate (SCJA) ) certification provides basic knowledge required to manage a Java project. The exam also tests your Java EE and Java ME basic skills. You can gain basic knowledge of Object-Oriented Concepts, UML representation of OO concepts, the Java programming language, and general knowledge of Java Platforms and Technologies.
Read this article =>
http://www.epractizelabs.com/blog2/?p=51
OCAJP 7 (new)
[More focused in Java SE 7 Programming basics]
Oracle Certified Associate, Java SE 7 Programmer certification provides basic knowledge required to program Java code. You need to complete Java SE 7 Programmer I Exam to achieve this certification. You can gain basic knowledge of Java data types, strings, arrays, loop constructs, methods and encapsulation, inheritance and exceptions.
Read this article =>
http://www.epractizelabs.com/blog2/?p=413
OCPJP 7 (certification path)
Note that to attend OCP, Java SE 7 exam
you should complete OCP Java SE 7 first under certification path.
Read this article about OCP Java SE 7 Exam (certification path ) =>
http://www.epractizelabs.com/blog2/?p=407
OCPJP 7 (upgrade path)
In the case of upgrade path you should have certified in any version Oracle Certified Professional, Java Programmer OR Any version Sun Certified Java Programmer.
Read this article about OCP Java SE 7 Upgrade Exam (upgrade path ) =>
http://www.epractizelabs.com/blog2/?p=397
Both these exams empower your knowledge of basic syntax and structure of the Java programming language and can create Java technology applications that run on server and desktop systems using Java SE 7.
Remember to study Java SE 7 features like binary literals, numbers with underscores, try with resources, exception handing enhancements, concurrency enhancements, switch with
string, diamond operator enhancements, etc.
Conclusion:
Till Java SE 6 there is no prerequisite to take Java Programmer Certification.
http://www.epractizelabs.com/blog2/?p=166
If you decide to take Java SE 6 certification, go ahead and complete Java Programmer exam.
If you decide to attend Java SE 7 certification, there is no option, you must complete OCA Java SE 7 prior to take OCP Java SE 7.
Thanks