Hi Janith,
Sounds like you already have the right foundation to start preparing for the exam. Apart from the things you mentioned, you will also need some knowledge on Security (firewalls,
applets), UML, Design Patterns (GoF), etc.
But it might be worth waiting till SCEA 5 Final is out.
Wherein you will also be tested in EJB 3, JPA,
JSF, Core J2EE Patterns, etc.
Good luck!