Best method to temporarily store/query data?
<p>I have an application that stores information about user temporarily. I don't want to mess with mysql because it's overkill - I need to store an id, user name, and some additional fields. I need to be able to easily query by the id, show all, or pull a list per-user.</p>

<p>A hash map would work ok but seems inefficient when needing to pull a list based on conditions. I'm still fairly new to java, but not programming, is are there a better database system or something that would work better for my task?</p>
