Hi All,
Thanks for all your help.
Here is the summary of how it goes for the problem of Mandatory MYSUNID at the first time of registration for SCJP exam.
Use
NONE@NONE.com for your first sun certification exam, without a MySunId prometric tool will not allow to register. Once you have given the exam MySunId would be sent to you thru the email Id you have provided in the Email contact while registering. This is the SUN ID that you need to furnish for the other exams which requires a prerequisite exams. There would be a MySunId genereted for you with the mail from the Sun cert Manager along with the details of account verfication code. With the verification code when you log into the www.certmanager.net/sun/, you would be able to create a account which will have the histroy of all the exams you have taken.
Have a good Luck. All the best!!!