Java & Security

I am getting ready to start coding an online java application that will be collecting personal information, all information will be stored in either an Access database or a MySQL database. What kind of security issues should I be worried about? Can anyone give me some suggestions? I would like to know about any security issues before I start coding so that I can resolve them as I go.

Your help is greatly appreciated.

Just the usuals SQL Injection and other popular problems. You can refer to the following article for help

This article may also help you. Used it in few occasions in web applications.