PreferencesClass

package java.util.prefs;
Preferences.class
private static PreferencesFactory factory1() {
	// 2. Try service provider interface
	Iterator i = Service.providers(PreferencesFactory.class,
				       ClassLoader.getSystemClassLoader());
	// choose first provider instance
	while (i.hasNext()) {
	    try {
		return (PreferencesFactory) i.next();
	    } catch (ServiceConfigurationError sce) {
		if (sce.getCause() instanceof SecurityException) {
		    // Ignore the security exception, try the next provider
		    continue;
		}
		throw sce;
	    }
	}

	// 3. Use platform-specific system-wide default
	String platformFactory =
	    System.getProperty("os.name").startsWith("Windows")
	    ? "java.util.prefs.WindowsPreferencesFactory"
	    : "java.util.prefs.FileSystemPreferencesFactory";
	try {
	    return ()
		Class.forName(platformFactory, false, null).newInstance();
	} catch (Exception e) {
	    InternalError error = new InternalError(
		"Can't instantiate platform default Preferences factory "PreferencesFactory
		+ platformFactory);
	    error.initCause(e);
	    throw error;
	}
    }

// to recover a configuration made before