This post originated from an RSS feed registered with Java Buzz by Marc Logemann. Original Post: use Preferences API for App Settings Feed Title: Marc's Java Blog Feed URL: http://www.logemann.org/day/index_java.xml Feed Description: Java related topics for all major areas. So you will see J2ME, J2SE and J2EE issues here. Latest Java Buzz Posts Latest Java Buzz Posts by Marc Logemann Latest Posts From Marc's Java Blog

One of the most forgotten new APIs in JDK 1.4 is certainly the Preferences API. In fact, among other developers, i was also quite unaware of the Preferences API, up until the time where i wondered where the application settings of my own created J2SE application are stored (no, i am not totally weird, but i am using JGoodies as GUI framework and i was abstracted from the Preferences API)

So why trashing the old properties style of programming when it comes to application preferences (i am not talking about i18n issues)

- properties have no naming convention on the filesystem
- properties can only handle strings
- properties only work (without pains) in the filesystem
- properties have no means of hierarchy

With the the Preferences API you can easily export your preferences tree to an XML document or let the system decide where to put the data. The PreferenceFactory is responsible for deciding where to put the prefs. Because PreferencesFactory is an interface, there are different implementations based on the JRE. On Windows you have the java.util.prefs.WindowsPreferencesFactory which in fact stores the preferences into the registry. Of course of not having a registry, on linux there is some other implementation available.

If you would like to have some other backing store, you would have to implement the PreferencesFactory for yourself and modify the system property "java.util.prefs.PreferencesFactory" to point to your implementation. At least thats how i would start, i havnt done it yet and never read anything about implementing an own PreferencesFactory.

Give Preferences API a try. At least for J2SE developers this is a must, because its so much easier handling settings like "current application screen size" or "current theme" for your application.