Message resource bundle

public class Messages { 
    // property file is: package/name/messages.properties
    private static final String BUNDLE_NAME = "package.name.messages";
    private static final ResourceBundle RESOURCE_BUNDLE = ResourceBundle.getBundle(BUNDLE_NAME);
    private Messages() {
    }
    public static String getString(String key) {
        try {
            return RESOURCE_BUNDLE.getString(key);
        } catch (MissingResourceException e) {
            return '!' + key + '!';
        }
    }
    public static String getString(String key, Object... params  ) {
        try {
            return MessageFormat.format(RESOURCE_BUNDLE.getString(key), params);
        } catch (MissingResourceException e) {
            return '!' + key + '!';
        }
    }
}