title: What's the best way to keep java app data stored redundantly in a file?
body: <p>If I have systems that are based on realtime data, how can I ensure that all the information that is current is redundantly stored in a file? So that when the program starts again, it uses this information to initialize itself back to where it was when it closed.</p>
  
  <p>I know of xstream and HSQLDB. but wasn't sure if this was the best option for data that needs to be a literal carbon copy.</p>