Listening for Changes to Preference Values in a Preference Node : Preference « Development « Java Tutorial

1. Java Tutorial
2. Development
3. Preference

import java.util.prefs.PreferenceChangeEvent;
import java.util.prefs.PreferenceChangeListener;
import java.util.prefs.Preferences;

public class Main {
  public static void main(String[] argv) throws Exception {

    Preferences prefs = Preferences.userNodeForPackage(String.class);

    prefs.addPreferenceChangeListener(new PreferenceChangeListener() {
      public void preferenceChange(PreferenceChangeEvent evt) {

        Preferences node = evt.getNode();
        String key = evt.getKey();
        String newValue = evt.getNewValue();
      }
    });
    prefs.put("key", "a string");
    prefs.put("key", "a new string");
    prefs.remove("key");
  }
}