This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
Raja - it's generally considered pretty poor form around here to post the same question in multiple forums. Two people have spent time answering your one (extremely vague) question. May I suggest that you brush up on HowToAskQuestionsOnJavaRanch.