Geetha,
Welcome to JavaRanch!
Your problem sounds most frustrating. I don't know of any sources other than
http://java.sun.com to download the JDK. To be able to download it 4 megabytes at a time would be appreciated by many modem users, I am sure.
If I were you, I'd ask someone I knew had a working copy for a copy, or if I thought my slow internet connection were the source of problems, I'd locate a high bandwidth connection to the internet at perhaps a university library or an internet cafe and download from there, or perhaps even search the internet for an alternate download location.
I wish I knew of an easier solution, but I cannot imagine one.
Good Luck.