I would like to ask some help on how to add/subtract a value in java from a certain value in a database. I need this very badly!! PLs HELP.

please show your code snippet.This is for helping and fixing problem and not for completing your assignments.First show your attempts and then we will help you.

As per what i understood,you need to connect your application to database . Then add or subtract it.
take a look at JDBC connectivity http://docs.oracle.com/javase/tutorial/jdbc/basics/index.html

why are you duplicating the threads http://www.daniweb.com/software-development/java/threads/450748/doing-calculations-and-saving-it-to-database#post1951158