The PreferencesFactory interface defines the factory methods used by the static methods of the Preferences class to obtain the root Preferences nodes for user-specific and system-wide preferences hierarchies. Application programmers never need to use this interface.

An implementation of the preferences API for a specific back-end data store must include an implementation of this interface that works with that data store. Sun's implementation of Java includes a default filesystem-based implementation, which you can override by specifying the name of a PreferencesFactory implementation as the value of the "java.util.prefs.PreferencesFactory" system property.

public interface PreferencesFactory {
// Public Instance Methods
     Preferences systemRoot( );  
     Preferences userRoot( );  
}