import java.io.FileOutputStream;
import java.util.prefs.Preferences;
public class PreferenceExample {
public static void main(String args[]) throws Exception {
Preferences prefsRoot = Preferences.userRoot();
Preferences myPrefs = prefsRoot.node("PreferenceExample");
myPrefs.put("A", "a");
myPrefs.put("B", "b");
myPrefs.put("C", "c");
System.out.print("Node's keys: ");
for (String s : myPrefs.keys()) {
System.out.print(s + "");
}
}
}