Refer this site:http://www.sun.com/training/certification/faq/index.html
* "Beginning with all Sun certification exams taken on or after August 1, 2003, certification offerings from Sun no longer have an expiration date. Rather, certification offerings are based on a version of technology."
* For exams taken after September 1, 2002, but prior to August 1, 2003, "Recertification was required to maintain one's status as a certified Sun professional after two years."