Naveen, all Sun certifications formally expire two years after you recieve the certificate.
You can still use the certification on business
cards and your CV, but the certification will be obsolete by then. Sun is making a single update examination available for an upgrade from the previous version of every certification, which probably means in the case of the
SCEA something akin to a repeat of Part 1. I don't believe you have to do the project or essay exam over again.
I think the upgrade exam costs less, also. In the UK the
SCJP exam costs �100, but the upgrade costs �70, for example.