I am looking for way to store some data. I want to users of my program to be able to choose a way to store data. They can choose database (PostgreSQL, MySQL) and I want to give opportunity to choose easier way for newbie users so they don't have to install database system. When they start my program for the first time they're passing user data (login/password) and the some data made by my program are stored on HDD of user. Is it any library (for Java) or something like db but configured automatically when that let me do this? I mean, I want to create some tables like in db and have an easy access to them. But they should be secured (access only with login/password passed at the first time). I hope you will understand me. It was difficult to explain what I want :)
You could use an embedded DB, like Apache Derby. See also the Working with encryption article.