This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Shivani, I'm not sure if I understand you correctly, but one possible approach is to load a stored JavaMail program in the Oracle database, and have a trigger call a PL/SQL wrapper procedure that invokes the JavaMail, and effectively sends an e-mail message. P.S. I covered this topic in detail in a book called Professional Oracle 8i Application Programming (ISBN: 1861004842), published by Wrox Press.