Hi Rahul,
I'm a beginner at Micro Edition development but i was searching about the same and even if i can't solve your problem maybe i can help you to find the way!
Mainly i would like to indicate this page that can guide you through the learning of how-to use RMS (that is the method to store data while using micro edition, it's possible to have anothers but
java works with portability, and the device to guarantee this on J2ME is the RMS),
http://www.ibm.com/developerworks/library/wi-rms/
Once you know how-to use the low-level data store api of micro edition you may find a way to structure your data for in a future you can retrieve and work it in the best way, but you have to keep in mind that you'll save everything as an array of bytes, so it's quite slow ..
I'm still looking for some way to structure my data to (de)serialize based on some kind of entity once i've the concept of recordset, i'll keep looking for some framework/lib that does that and if i find something i'll notify you!
Feel free to ask anything you want and visit
BlackBeltFactory, there is a lot of courses that can help you with any subject related to java! Cheers o/