Parambir Singh wrote:The SCJP certification is valid for 3 years only, isn't it?
No. Who told you that? Sun's
SCWCD page says:
To achieve this certification, candidates must successfully complete one exam. Prior to attempting certification, candidates must be certified as a Sun Certified Programmer (SCJP), any edition.
It does not say that your SCJP certificate must be less than 3 years old. Also, Sun's certification pages do not mention anywhere that any of the certificates expires after a certain time. Your SCJP certificate never expires.