import java.util.prefs.Preferences;
public class Main {
public static void main(String[] argv) throws Exception {
Preferences prefs = Preferences.userNodeForPackage(java.lang.String.class);
Preferences node = prefs.parent(); // /java
node = node.parent(); // null
String[] names = null;
names = prefs.childrenNames();
for (int i = 0; i < names.length; i++) {
node = prefs.node(names[i]);
}
}
}