import java.util.prefs.Preferences;
public class Main {
public static void main(String[] argv) throws Exception {
// Get the user preference node for java.lang
Preferences prefs = Preferences.userNodeForPackage(String.class);
// Remove a preference in the node
final String PREF_NAME = "name_of_preference";
prefs.remove(PREF_NAME);
// Remove all preferences in the node
prefs.clear();
}
}