Hi, Dipti, and welcome to the Ranch!
Can you plase
TellTheDetails about what you're doing and where the error is coming from? How are you running your program? Is it an
applet, a standalone app, or something else? Are you running it inside Eclipse? If so, have you tried running on the command line? What are the permission settings on the rt.jar file, and which user owns it? Is this error message part of an exception with stack trace? If so, please copy/paste the whole error message. Or is it coming from outside the execution of your program?
The more details you provide about what you're doing and what results you're seeing, the better the chance somebody will be able to help you.