Hi Jaya,
If your "manual testing" role only involves running the complete application and executing test cases and/or trying to find bugs from an end user perspective, then the SCJP probably will not help you very much. You might benefit from understanding the exception messages that you'll see for some bugs, and you might have a better idea of how to look for concurrency-related issues. But honestly an SCJP certification would be overkill for such a job role, IMO.
On the other hand, if your current or future testing role also includes activities like static code analysis, profiling, or debugging, then you're much more likely to benefit from having an SCJP-level understanding of Java.
Still,
you should be aware that the SCJP certification is first and foremost a developer certification. If your job scope doesn't include actual Java development, then the certification won't be as relevant. However, once you have an SCJP certificate, then you'll likely be qualified for at least junior programmer roles... so perhaps it'll open up new opportunities for you beyond testing. (But I agree that you should also get some
J2EE training if you don't have formal programming-related qualifications.)
[ November 22, 2007: Message edited by: Kelvin Lim ]