The following is coverage on the OCAJ 5/6 that is not on the OCAJ 7:
Java Platforms and Integration Technologies
--> Distinguish the basic characteristics of the three Java platforms: J2SE, J2ME, and J2EE, and given a high-level architectural goal, select the appropriate Java platform or platforms.
--> Describe at a high level the benefits and basic characteristics of RMI.
--> Describe at a high level the benefits and basic characteristics of JDBC, SQL, and RDBMS technologies.
--> Describe at a high level the benefits and basic characteristics of JNDI, messaging, and JMS technologies.
Client Technologies
--> Describe at a high level the basic characteristics, benefits and drawbacks of creating thin-clients using HTML and JavaScript and the related deployment issues and solutions.
--> Describe at a high level the basic characteristics, benefits, drawbacks, and deployment issues related to creating clients using J2ME midlets.
--> Describe at a high level the basic characteristics, benefits, drawbacks, and deployment issues related to creating fat-clients using Applets.
--> Describe at a high level the basic characteristics, benefits, drawbacks, and deployment issues related to creating fat-clients using Swing.
Server Technologies
--> Describe at a high level the basic characteristics of: EJB, servlets, JSP, JMS, JNDI, SMTP, JAX-RPC, Web Services (including SOAP, UDDI, WSDL, and XML), and JavaMail.
--> Describe at a high level the basic characteristics of servlet and JSP support for HTML thin-clients.
--> Describe at a high level the use and basic characteristics of EJB session, entity and message-driven beans.
--> Describe at a high level the fundamental benefits and drawbacks of using J2EE server-side technologies, and describe and compare the basic characteristics of the web-tier, business-tier, and EIS tier.
So, if you have a need to certify your expertise/experience in these areas (relative to these objectives)... take the OCAJ 5/6.
Note that the end-of-public-updates for Java SE 6 is November of this year (2012) - http://www.oracle.com/technetwork/java/eol-135779.html
Java Platforms and Integration Technologies
--> Distinguish the basic characteristics of the three Java platforms: J2SE, J2ME, and J2EE, and given a high-level architectural goal, select the appropriate Java platform or platforms.
--> Describe at a high level the benefits and basic characteristics of RMI.
--> Describe at a high level the benefits and basic characteristics of JDBC, SQL, and RDBMS technologies.
--> Describe at a high level the benefits and basic characteristics of JNDI, messaging, and JMS technologies.
Client Technologies
--> Describe at a high level the basic characteristics, benefits and drawbacks of creating thin-clients using HTML and JavaScript and the related deployment issues and solutions.
--> Describe at a high level the basic characteristics, benefits, drawbacks, and deployment issues related to creating clients using J2ME midlets.
--> Describe at a high level the basic characteristics, benefits, drawbacks, and deployment issues related to creating fat-clients using Applets.
--> Describe at a high level the basic characteristics, benefits, drawbacks, and deployment issues related to creating fat-clients using Swing.
Server Technologies
--> Describe at a high level the basic characteristics of: EJB, servlets, JSP, JMS, JNDI, SMTP, JAX-RPC, Web Services (including SOAP, UDDI, WSDL, and XML), and JavaMail.
--> Describe at a high level the basic characteristics of servlet and JSP support for HTML thin-clients.
--> Describe at a high level the use and basic characteristics of EJB session, entity and message-driven beans.
--> Describe at a high level the fundamental benefits and drawbacks of using J2EE server-side technologies, and describe and compare the basic characteristics of the web-tier, business-tier, and EIS tier.
So, if you have a need to certify your expertise/experience in these areas (relative to these objectives)... take the OCAJ 5/6.
Note that the end-of-public-updates for Java SE 6 is November of this year (2012) - http://www.oracle.com/technetwork/java/eol-135779.html