Testing the app without persistent state was getting annoying, so I did a bit of research and discovered the java.utils.prefs features for storing and retrieving preferences. Documentation is pretty sparse, but eventually I found this tutorial which shows how easy this stuff is to use. I soon had the app saving and restoring its window position and size, and the position of it splitter bars. That's all I need for this app, but future apps will probably benefit from a full class which saves the state of all relevant components in a JFrame, like the FormState class I wrote for Delphi.

The Preferences class stores data in an appropriate place based on the underlying platform; on Windows, that turns out to be the system registry, and all user-level Java app preferences are stored in the same location: HKEY_CURRENT_USER\Software\JavaSoft\Prefs. That means it's important to have your class hierarchy properly rooted and unique, so I refactored the application so that its main package is ca.uvic.hcmc.apparatus.gui.